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  • 1. Adachi, N.
    et al.
    Denysenkov, V. P.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Okuda, T.
    Epitaxial Bi3Fe5O12(001) films grown by pulsed laser deposition and reactive ion beam sputtering techniques2000Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 88, nr 5, s. 2734-2739Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on processing and comparative characterization of epitaxial Bi3Fe5O12 (BIG) films grown onto Gd-3(ScGa)(5)O-12[GSGG,(001)] single crystal using pulsed laser deposition (PLD) and reactive ion beam sputtering (RIBS) techniques. A very high deposition rate of about 0.8 mu m/h has been achieved in the PLD process. Comprehensive x-ray diffraction analyses reveal epitaxial quality both of the films: they are single phase, exclusively (001) oriented, the full width at half maximum of the rocking curve of (004) Bragg reflection is 0.06 deg for PLD and 0.05 deg for RIBS film, strongly in-plane textured with cube-on-cube film-to-substrate epitaxial relationship. Saturation magnetization 4 pi M-s and Faraday rotation at 635 nm were found to be 1400 Gs and -7.8 deg/mu m in PLD-BIG, and 1200 Gs and -6.9 deg/mu m in RIBS-BIG. Ferromagnetic resonance (FMR) measurements performed at 9.25 GHz yielded the gyromagnetic ratio gamma=1.797x10(7) l/s Oe, 1.826x10(7) l/s Oe; the constants of uniaxial magnetic anisotropy were K-u(*)=-8.66x10(4) erg/cm(3), -8.60x10(4) erg/cm(3); the cubic magnetic anisotropy K-1=-2.7x10(3) erg/cm(3),-3.8x10(3) erg/cm(3); and the FMR linewidth Delta H=25 and 34 Oe for PLD and RIBS films correspondingly. High Faraday rotation, low microwave loss, and low coercive field less than or equal to 40 Oe of BIG/GSGG(001) films promise their use in integrated magneto-optic applications.

  • 2.
    Ansari, Nazanin
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Grishin, Alexander
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Multicolor filter all-garnet magneto-optical photonic crystals2012Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, nr 17, s. 3552-3554Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate a multicolor optical filter and isolator based on a double-cavity magneto-optical (MO) photonic crystal. Being grown as a heteroepitaxial all-garnet multilayer, it compromises a strong MO response and high optical transmittance. Low-loss, high Faraday rotation passbands as well as strong light rejection within the stop band were achieved by optimization of distance between cavities and repetition number of distributed Bragg reflectors.

  • 3. Balinsky, Michael
    et al.
    Ranjbar, Mojtaba
    Haidar, Mohammad
    Durrenfeld, Philipp
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Slavin, Andrei
    Åkerman, Johan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF. University of Gothenburg, Sweden.
    Dumas, Randy K.
    Spin Pumping and the Inverse Spin-Hall Effect via Magnetostatic Surface Spin-Wave Modes in Yttrium-Iron Garnet/Platinum Bilayers2015Ingår i: IEEE Magnetics Letters, ISSN 1949-307X, E-ISSN 1949-3088, Vol. 6, nr 3000604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spin pumping at a boundary between a yttrium-iron garnet (YIG) film and a thin platinum (Pt) layer is studied under conditions in which a magnetostatic surface spin wave (MSSW, or Damon-Eshbach mode) is excited in YIG by a narrow strip-line antenna. It is shown that the voltage created by the inverse spin-Hall effect (ISHE) in Pt is strongly dependent on the wavevector of the excited MSSW. For YIG film thicknesses of 41 and 0.9 mu m, the maximum ISHE voltage corresponds to the maximum of efficiently excited MSSW wavevectors and does not coincide with the maximum of absorbed microwave power. For a thinner (0.175 mu m) YIG film, the maximum of the ISHE voltage moves closer to the ferromagnetic resonance and almost coincides with the region of the maximum microwave absorption. We show that the effect is related to the change in the thickness profile and the wavenumber spectrum of the excited MSSW taking place when the YIG film thickness is increased.

  • 4. Belotelov, V. I.
    et al.
    Kreilkamp, L. E.
    Akimov, I. A.
    Kalish, A. N.
    Bykov, D. A.
    Kasture, S.
    Yallapragada, V. J.
    Gopal, Achanta Venu
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Nur-E-Alam, M.
    Vasiliev, M.
    Doskolovich, L. L.
    Yakovlev, D. R.
    Alameh, K.
    Zvezdin, A. K.
    Bayer, M.
    Plasmon-mediated magneto-optical transparency2013Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 4, s. 2128-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Magnetic field control of light is among the most intriguing methods for modulation of light intensity and polarization on sub-nanosecond timescales. The implementation in nanostructured hybrid materials provides a remarkable increase of magneto-optical effects. However, so far only the enhancement of already known effects has been demonstrated in such materials. Here we postulate a novel magneto-optical phenomenon that originates solely from suitably designed nanostructured metal-dielectric material, the so-called magneto-plasmonic crystal. In this material, an incident light excites coupled plasmonic oscillations and a waveguide mode. An in-plane magnetic field allows excitation of an orthogonally polarized waveguide mode that modifies optical spectrum of the magneto-plasmonic crystal and increases its transparency. The experimentally achieved light intensity modulation reaches 24%. As the effect can potentially exceed 100%, it may have great importance for applied nanophotonics. Further, the effect allows manipulating and exciting waveguide modes by a magnetic field and light of proper polarization.

  • 5. Belotelov, V. I.
    et al.
    Kreilkamp, L. E.
    Kalish, A. N.
    Akimov, I. A.
    Bykov, D. A.
    Kasture, S.
    Yallapragada, V. J.
    Gopal, A. V.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Nur-E-Alam, M.
    Vasiliev, M.
    Doskolovich, L. L.
    Yakovlev, D. R.
    Alameh, K.
    Zvezdin, A. K.
    Bayer, M.
    Magnetophotonic intensity effects in hybrid metal-dielectric structures2014Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 89, nr 4, s. 045118-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The magneto-optical properties of a hybrid metal-dielectric structure consisting of a one-dimensional gold grating on top of a magnetic waveguide layer are studied experimentally and theoretically. It is demonstrated that a magnetic field applied in the longitudinal configuration (in the plane of the magnetic film and perpendicular to the slits in the gold grating) to the metal-dielectric structure modifies the field distribution of the optical modes and thus changes the mode excitation conditions. In the optical far field, this manifests in the alteration of the optical transmittance or reflectance when the structure becomes magnetized. This magneto-optical effect is shown to represent a novel class of effects related to the magnetic-field-induced modification of the Bloch modes of the periodic hybrid structure. That is why we define this effect as "longitudinal magnetophotonic intensity effect" (LMPIE). The LMPIE has two contributions, odd and even in magnetization. While the even LMPIE is maximal for the light polarized perpendicular to the grating slits (TM) and minimal for the orthogonal polarization (TE), the odd LMPIE takes maximum values at some intermediate polarization and vanishes for pure TM and TE polarizations. Two principal modes of the magnetic layer - TM and TE - acquire in the longitudinal magnetic field additional field components and thus turn into quasi-TM and quasi-TE modes, respectively. The largest LMPIE is observed for excitation of the antisymmetrical quasi-TE mode by TM-polarized light. The value of the LMPIE measured for the plasmonic structure with a magnetic film of Bi2Dy1Fe4Ga1O12 composition is about 1% for the even effect and 2% for the odd one. However, the plasmonic structure with a magnetic film with a higher concentration of bismuth (Bi2.97Er0.03Fe4Al0.5Ga0.5O12) gives significantly larger LMPIE: even LMPIE reaches 24% and odd LMPIE is 9%. Enhancement of the magneto-optical figure of merit (defined as the ratio of the specific Faraday angle of a magnetic film to its absorption coefficient) of the magnetic films potentially causes the even LMPIE to exceed 100% as is predicted by calculations. Thus, the nanostructured material described here may be considered as an ultrafast magnetophotonic light valve.

  • 6.
    Blomqvist, Mats
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Electro-optic effect in ferroelectric Na0.5K0.5NbO3 thin films on oxide substrates2006Ingår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 80, nr 1, s. 97-106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have deposited Na0.5NbO3 (NKN) films oil single crystal Al2O3(1 (1) under bar 02) and SrTiO3(001) substrates using rf-magnetron sputtering of a stoichiometric, high-density ceramic target. Using x-ray diffraction it was confirmed that NKN grows preferentially c-axis oriented on sapphire substrate and epitaxially oil the perovskite SrTiO3(001) substrate. Electro-optical (EO) properties were measured in visible light through a transverse method. With an applied dc field up to 20 kV/cm, the effective linear EO response was determined to r(eff) = 28 pm/V for NKN/Al2O3 and r(eff) = I I pm/V for NKN/SrTiO3, where a superlinear dependence was observed.

  • 7.
    Blomqvist, Mats
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Electrooptic ferroelectric Na0.5K0.5NbO3 films2005Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 17, nr 8, s. 1638-1640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on waveguiding and electrooptic properties of epitaxial Na0.5K0.5NbO3 films grown by radio-frequency magnetron sputtering on Al2O3 (1102) single crystal substrates. High optical waveguiding performance has been demonstrated in infrared and visible light. The in-plane electrooptic effect has been recorded in transmission using a transverse geometry. At dc fields, the effective linear electrooptic coefficient was determined to 28 pm/V, which is promising for modulator applications.

  • 8.
    Blomqvist, Mats
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Visible and IR light waveguiding in ferroelectric Na0.5K0.5NbO3 thin films2005Ingår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 69, s. 277-286Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-quality ferroelectric thin films are attractive materials for integrated optics applications including electro-optic waveguide modulators and frequency doubling secondharmonic generators. Several fefroelectric thin film materials, such as BaTiO3, KNbO3, LiNbO3, and (Pb,La)(ZrTi)O-3, have been investigated regarding their optical and waveguiding properties. Recently the first results on waveguiding in ferroelectric Na0.5K0.5NbO3 (NKN) thin films were presented. Perovskite NKN films have previously been investigated as electrically tunable material for low loss rf and microwave applications. Na0.5K0.5NbO3 thin films of thickness 0.5-1.0 mum have been deposited on Nd:YAlO3(001) and Al2O3(0112) substrates using rf-magnetron sputtering of a stoichiometric, high-density ceramic target. X-ray diffraction measurements confirmed films grown highly (00l) oriented on the perovskite Nd:YAlO3 substrate and preferentially c-axis oriented on the single crystal r-cut sapphire substrate. Optical and waveguiding properties were characterized using a Metricon 2010 prism-coupling apparatus with a rutile prism. Dark-line spectra were obtained at visible light (lambda = 632.8 nm) as well as at infrared optical communication wavelengths, lambda = 1319 nm and lambda = 1549 nm, in both transverse electric (TE) and transverse magnetic (TM) polarizations. Sharp dips corresponding to waveguide propagation modes in the thin film layers where observed for both substrates. The calculated refractive index values and corresponding birefringence (Deltan = n(TM) - n(TE) = n(e) - n(o)) as a function of wavelength has been compared. Generally a larger birefringence is observed for the NKN film on Nd:YAlO3, which is in agreement with the larger degree of preferential c-axis orientation measured by XRD.

  • 9.
    Blomqvist, Mats
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Petraru, Adrian
    Institute of Thin Films and Interfaces, Section: Ion Technology, Forschungzentrum Jülich.
    Rf sputtered Na0.5K0.5NbO3 films on oxide substrates as optical waveguiding material2003Ingår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 54, s. 631-640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Highly crystalline Na0.5K0.5NbO3 (NKN) thin films of 1-2 mum thickness were deposited by rf-magnetron sputtering of a stoichiometric, ceramic target on single crystal LaAlO3 (001) and Al2O3 (01 (1) under bar2) substrates. X-ray diffraction measurements revealed epitaxial quality of NKN/LaAlO3 film structures, whereas NKN films on sapphire substrates were found to be preferentially c -axis oriented. A prism-coupling technique was used to characterize optical and waveguiding properties. A bright-line spectrum at lambda = 632.8 nm, revealed sharp peaks, corresponding to transverse magnetic (TM) and electric (TE) waveguide propagation modes in NKN/LaAlO3 and NKN/Al2O3 thin films. Using a least mean square fit the refractive index for the films and film thickness were calculated. The extraordinary and ordinary refractive indices were determined to n(e) = 2.207 +/- 0.002 and n(o) = 2.261 +/- 0.002, and n(e) = 2.216 +/- 0.002 and n(o) = 2.247 +/- 0.002 at lambda = 632.8 nm for 2.0 mum thick NKN films on LaAlO3 and Al2O3 , respectively. This corresponds to a birefringence Deltan = n(e) - n(o) = -0.054 +/- 0.003 and Deltan = -0.031 +/- 0.003 in the films, where the larger Deltan for the NKN/LaAlO3 structure can be explained by the superior crystalline quality compared to NKN/Al2O3 . Atomic force microscopy images of the film surfaces revealed rms roughnesses of 2.5 nm and 8.0 nm for 1.0-mum thick NKN/LaAlO3 and NKN/Al2O3 films, respectively. We believe surface scattering is one of the main sources of waveguide losses in the thin films.

  • 10.
    Blomqvist, Mats
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Petraru, Adrian
    Inst. of Thin Films and Interfaces, Section: Ion Technology, Forschungszentrum Jülich.
    Buchal, Christoph
    Inst. of Thin Films and Interfaces, Section: Ion Technology, Forschungszentrum Jülich.
    Optical waveguiding in magnetron-sputtered Na0.5K0.5NbO3 thin films on sapphire substrates2003Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 82, nr 3, s. 439-441Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Preferentially oriented perovskite-structured Na0.5K0.5NbO3 (NKN) thin films have been deposited on hexagonal Al2O3(01 (1) under bar2) substrates using rf magnetron sputtering of a stoichiometric, high-density, ceramic target. Structural and film surface properties were measured using x-ray diffraction and atomic force microscopy, respectively. Optical and waveguiding properties were characterized using a prism-coupling technique. We observed sharp and distinguishable TM and TE propagation modes and measured the refractive index of NKN thin films of different thicknesses. The ordinary and extraordinary refractive indices were calculated to be n(o)=2.247+/-0.002 and n(e)=2.216+/-0.002 for a 2.0-mum-thick film at 632.8 nm. This implies a birefringence Deltan=n(e)-n(o)=-0.031+/-0.002 in the film. These first results show the potential use of rf-sputtered NKN films as an electro-optical active material.

  • 11.
    Blomqvist, Mats
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Koh, Jung-Hyuk
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Rf-magnetron sputtered ferroelectric (Na,K)NbO3 films2002Ingår i: Proceedings of the 13th IEEE International Symposium on Applications of Ferroelectronics / [ed] White, G.; Tsurumi, T., 2002, s. 195-198Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sodium potassium niobate (Na,K)NbO3 (NKN) thin films were grown by rf-magnetron sputtering from stoichiometric Na0.5K0.5NbO3 target on LaAlO3 (LAO) single crystals and polycrystalline Pt80Ir20 (PtIr) substrates. NKN films on polycrystalline PtIr substrates were found to be preferentially (004 oriented while XRD measurements reveal epitaxial quality of NKN/LaAlO3 film structures. The ferroelectric state in NKN/PtIr films at room temperature is indicated by polarization loops with polarization as high as 33.4 muC/cm(2) at 700 kV/crn, remnant polarization of 9.9 muC/cm(2), and coercive field of 91 kV/cm. I-V characteristics of vertical Au/NKN/PtIr capacitive cells and planar Au/NKN/LAO interdigital capacitors (IDCs) showed very good insulating properties. For NKN IDC the leakage current density was in the order of 30 nA/cm(2) at 400 kV/cm. Rf dielectric spectroscopy demonstrates low loss, low frequency dispersion, and high voltage tunability both for vertical Au/NKN/PtIr and planar interdigital Au/NKN/LAO capacitors.

  • 12.
    Blomqvist, Mats
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Koh, Jung-Hyuk
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Andréasson, Johanna
    Department of Materials and Manufacturing Engineering, Luleå University of Technology.
    High-performance epitaxial Na0.5K0.5NbO3 thin films by magnetron sputtering2002Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, nr 2, s. 337-339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial Na0.5K0.5NbO3 (NKN) thin films have been grown on LaAlO3 substrates by rf magnetron sputtering of a stoichiometric, high-density, ceramic target. X-ray diffraction analysis showed c-axis oriented cube-on-cube growth. Micrometer size interdigital capacitor (IDC) structures were defined on the surface of the NKN film using photolithography. The electrical characterization at 1 MHz showed dissipation factor tan delta of 0.010, tunability 16.5% at 200 kV/cm and dielectric permittivity epsilon(r)=470. The frequency dispersion of epsilon(r) between 1 kHz and 1 MHz was 8.5% and the IDCs showed very good insulating properties with leakage current density on the order of 30 nA/cm(2) at 400 kV/cm. The polarization loop exhibits weak ferroelectric hysteresis with maximum polarization 23.5 muC/cm(2) at 600 kV/cm. These results are promising for tunable microwave devices based on rf sputtered NKN thin films.

  • 13.
    Bonetti, Stefano
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Kim, Jang-Yong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Grishin, Alexander
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Buried tantalate-niobate microwave varactors2007Ingår i: 2006 15TH IEEE INTERNATIONAL SYMPOSIUM ON APPLICATIONS OF FERROELECTRICS, 2007, s. 347-350Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present characteristics of microwave variable capacitors (varactors) buried in 2.5 mu m thick AgTa0.5Nb0.5O3 (ATN) film pulsed laser deposited on sapphire single crystal. 2 gm gap interdigital capacitors (IDC) were fabricated by photolithographic, dry etching and lift-off processes. For comparison, similar IDCs were also defined on top of ATN film. Capacitance and loss tangent have been determined using a modified de-embedding technique in the microwave range 25 MHz - 40 GHz. Buried structures show higher values of capacitance and tunability, keeping the same level of losses compared to standard topped devices and resulting in an increased K-factor = tunability/tan delta. Experimental results are explained within equivalent circuit model. Besides the increased performance, the new design avoids the need of a successive planarization step, which could be required in an integration process.

  • 14. Brunahl, J.
    et al.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Non-destructive pulsed technique to characterize functional properties of micromachined bulk PZT2001Ingår i: Ferroelectrics (Print), ISSN 0015-0193, E-ISSN 1563-5112, Vol. 263, nr 1-4, s. 1487-1492Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this report, a non-destructive pulsed technique is presented to characterize all relevant properties of machined bulk PZT material. The proposed method is based on recording of the transient current as response on the short voltage pulse applied to the ferroelectric acoustic element. This new promising experimental technique makes it possible to measure mechanical and electrical properties fast, reliably and reproducibly. Among other results we can obtain electromechanical coupling coefficient, dielectric loss factor tan 8, mechanical quality factor Q, dielectric constant, capacitance, resonant frequency and Curie temperature T-c. The temperature dependence of above mentioned parameters can be studied as well very easily.

  • 15. Dyakonov, V.
    et al.
    Prohorov, A.
    Shapovalov, V.
    Khartsev, Sergiy
    Krivoruchko, V.
    Mihailov, V.
    Pashchenko, V.
    Zubov, E.
    Aleshkevych, P.
    Dyakonov, K.
    Piechota, S.
    Szymczak, H.
    Spin-wave resonance in the La0.7Mn1.3O3-delta film2000Ingår i: Physics Letters A, ISSN 0375-9601, E-ISSN 1873-2429, Vol. 268, nr 3, s. 202-207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The spin-wave resonance (SWR) spectra have been observed in the (001) oriented La0.7Mn1.3O3-delta epitaxial films. The spectra consist of a series of well-resolved spin-wave modes clearly seen in the: perpendicular external field configuration. It is shown that the spins are completely pinned on both sides of the film surface. Based on a study of the SWR spectra the value of the spin-wave exchange constant, D, is found to be 150 meV Angstrom(2). This value of. D correlates well with this one determined for all known until now manganites.

  • 16.
    Emmoth, Birger
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Pisarev, A.
    Grishin, Alexander
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Karlsson, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Litnovsky, A.
    Rubel, Marek J.
    KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.
    Wienhold, P.
    Fuel removal from bumper limiter tiles by using a pulsed excimer laser2005Ingår i: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 337-39, nr 1-3, s. 639-643Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Samples of a limiter tile from the TEXTOR tokamak were investigated by scanning electron microscopy and nuclear reaction analysis both before and after laser heating. SEM images showed spheres and thin flakes covering the surface which are the areas modified by plasma particles striking under grazing angles. Due to roughness of the surface there are shadowed regions between the 'flakes'. Laser pulses did not lead to expected common ablation of the surface. Features that looked like 'melting' of thin surface layers were rather observed. The initial deuterium content in the surface layer of tiles was of the order of 10(18) D atoms per cm(2). After the laser light impact the content decreased with 60-70%; by reducing the deposited power by a factor four, the deuterium content was decreased by 40-50%. We make the interpretation that we approach a threshold of the laser detritiation method in fusion devices.

  • 17.
    Fornara, Andrea
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Vogt, Carmen
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Li, Shanghua
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Qin, Jian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Toprak, Muhammet
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Grishin, Alexander
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Synthesis, characterization and magneto-optical properties of transparent magnetic PMMA/nanoparticles compositeManuskript (preprint) (Övrigt vetenskapligt)
  • 18. Fors, R.
    et al.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Giant resistance switching in metal-insulator-manganite junctions: Evidence for Mott transition2005Ingår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 71, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heteroepitaxial CeO2(80 nm)/L0.67Ca0.33MnO3(400 nm) film structures have been pulsed laser deposited on LaAlO3(001) single crystals to fabricate two terminal resistance switching devices. Ag/CeO2/L0.67Ca0.33MnO3 junctions exhibit reproducible switching between a high resistance state (HRS) with insulating properties and a semiconducting or metallic low resistance state (LRS) with resistance ratios up to 10(5). Reversible electrical switching is a polar effect achievable both in continuous sweeping mode and in the pulse regime. Successive temperature crossover of electronic transport from the thermal activation of the deep levels (E-a=320 meV) at high temperatures to thermal activation of the shallow levels (E-a=40 meV) and finally at low temperatures to the regime of temperature independent resistance, usually associated with quantum tunneling, has been found for the insulating HRS. The temperature dependence of the LRS reveals a para-to-ferromagnetic phase transition in the L0.67Ca0.33MnO3 (LCMO) electrode at T-c=260 K and an anomaly at lower temperatures similar to200 K corresponding to the Curie temperature of the Mn4+ depleted part of the LCMO film. Current-voltage characteristics in the LRS are highly nonlinear, and show negative differential conductivity (NDC). We suggest that the reversible resistance switching ocurrs due to the electric field induced nucleation of filament-type conducting valence-shifted CeOx domains inside the insulating CeO2 matrix. The abrupt insulator-to-metal transition is the result of localization of 4f electronic states in Ce3+ ions and the subsequent appearance of hole conductivity in the oxygen p-bands. NDC at low temperatures is relied upon the interband scattering of CeOx carriers from a low energy, high mobility valley into a high energy valley with low mobility.

  • 19.
    Fors, Rickard
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Khartsev, Sergiy
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Grishin, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Non-volatile giant resistance switching in metal-insulator-manganite junctions2005Ingår i: Materials and Processes for Nonvolatile Memories / [ed] Claverie, A; Tsoukalas, D; King, TJ; Slaughter, JM, WARRENDALE: MATERIALS RESEARCH SOCIETY , 2005, Vol. 830, s. 379-384Konferensbidrag (Refereegranskat)
    Abstract [en]

    Heteroepitaxial CeO2(80nm)/L0.67Ca0.33MnO3(400nm) film structures have been pulsed laser deposited on LaAlO3(001) single crystals to fabricate two terminal resistance switching devices. Ag/CeO2/L0.67Ca0.33MnO3 junctions exhibit reproducible switching between a high resistance state (FIRS) with insulating properties and a semiconducting or metallic low resistance state (LRS) with resistance ratios up to 10(5). Reversible electrical switching is a polar effect achievable both in continuous sweeping mode and in the pulse regime.

  • 20.
    Fors, Rickard
    et al.
    KTH, Tidigare Institutioner, Materialvetenskap.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Pohl, A.
    Westin, G.
    Sol-gel derived versus pulsed laser deposited epitaxial La0.67Ca0.33MnO3 films: structure, transport and effects of post-annealing2004Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 467, nr 02-jan, s. 112-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaAlO3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post annealing at 1000 degreesC. Transport measurements show maximum temperature coefficient of resistivity of 8.2% K-1 at 258 K (PLD) and 6.1% K-1 at 241 K (sol-gel) and colossal magnetoresistance at 560 kA/m of 35% at 263 K (PLD) and 32% at 246 K (sol-gel).

  • 21.
    Fors, Rickard
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Pohl, A.
    Khartsev, Sergey
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Westin, G.
    Comparison of sol-gel derived and pulsed laser deposited epitaxial La0.67Ca0.33MnO3 films for IR bolometer2004Ingår i: Integration Of Advanced Micro-And Nanoelectronic Devices-Critical Issues And Solutions / [ed] Morais, J; Kumar, D; Houssa, M; Singh, RK; Landheer, D; Ramesh, R; Wallace, RM; Guha, S; Koinuma, H, 2004, Vol. 811, s. 379-384Konferensbidrag (Refereegranskat)
    Abstract [en]

    Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaAlO3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post-annealing at 1000 degreesC. Transport measurements show maximum temperature coefficient of resistivity of 8.2 % K-1 at 258 K (PLD) and 6.1% K-1 at 241 K (sol-gel) and colossal magnetoresistance at 7 kOe of 35% at 263 K (PLD) and 32% at 246 K (sol-gel).

  • 22.
    Grishin, A. M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, S. I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Bohlmark, J.
    Ahlgren, M.
    Ultra-hard AlMgB14 Coatings Fabricated by RF Magnetron Sputtering from a Stoichiometric Target2015Ingår i: JETP Letters: Journal of Experimental And Theoretical Physics Letters, ISSN 0021-3640, E-ISSN 1090-6487, Vol. 100, nr 10, s. 680-687Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the first time hard aluminum magnesium boride films were fabricated by RF magnetron sputtering from a single stoichiometric ceramic AlMgB14 target. Optimized processing conditions (substrate temperature, target sputtering power and target-to-substrate distance) enable fabrication of stoichiometric in-depth compositionally homogeneous films with the peak values of nanohardness 88 GPa and Young's modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 and 275 GPa at 200 nm depth in 2 mu m thick film.

  • 23.
    Grishin, Alexander
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergey
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Electro-optical properties of Na0.5K0.5NbO3 films on Si by free-space coupling technique2004Ingår i: New Materials For Microphotonics / [ed] Shin, JH; Brongersma, M; Buchal, C; Priolo, F, 2004, Vol. 817, s. 225-229Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report electro-optic performance of highly polar axis oriented Na0.5K0.5NbO3 (NKN) films grown directly on Pt(100nm)/Ti(10nm)/SiO2/Si(001) substrates by rf-magnetron sputtering. Semitransparent gold electrodes (diameter circle divide = 2 mm) were deposited ontop the NKN films by a thermal evaporation through the contact mask. Processing parameters have been specially optimized to obtain "electrosoft" NKN films with a non-linear fatigue-free P-E characteristics: low remnant P-r = 3.6 muC/cm(2) and high induced polarization P = 26 muC/cm(2) @ 522 kV/cm, and the coercive field E-c = 39 kV/cm. Electro-optical characterization of NKN/Pt/Si films has been performed using waveguide refractometry: a free-space coupling of a light beam into the thin-film waveguide modes. Intensity of TM- and TE-polarized light of 670 nm laser diode reflected from the free surface of NKN film and Au-cladding NKN/PL/Si waveguide was recorded at zero and 30 V (100 kV/cm) bias electric field. Extraordinary and ordinary refractive indices as well as electro-optic coefficient have been determined by fitting these experimental data to the Fresnel formulas. Applying 160 V (530 kV/cm) across the parallel plate NKN capacitor (circle divide = 2 mm, thickness 3 mum), modulation of the reflected light as high as 40% was achieved.

  • 24.
    Grishin, Alexander
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Khartsev, Sergey
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Dzibrou, Dzmitry
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Enhanced photoluminescence in [Er2O3/TiO2]m photonic crystals2009Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 105, nr 11, s. 113122-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We survey optical properties of [Er2O3/TiO 2]6/Er2O32/[TiO 2/Er2O3]6 photonic crystals (PCs) pulsed laser deposited on to the glass substrates. The dispersion relations of refractive indexes and extinction coefficients of the constituent materials were obtained from the comparison of experimental and simulated transmission spectra of single layer Er2O3 and TiO2 reference films. Based on these data several PCs have been designed and grown to match stop band and cavity mode resonance at wavelengths close to the 523 nm Er 3+-ion Fraunhofer 4S3/2 absorption line. Precise control of chemical composition and uniform multilayer thickness enable achievement of superior optical performance of sintered PCs. Obtained dispersion relations were combined with the 2×2 transfer matrix formalism to compute PC transmittance that appeared to be in a good agreement with the experimental spectra. Pumping PCs with 514 nm light source we observed a strong photoluminescence (PL) at 1535 nm. In PC specially designed for the resonance wavelength λres =514 nm, C-band PL intensity experiences fivefold enhancement compared to a single layer Er2 O3 film of equivalent thickness.

  • 25.
    Grishin, Alexander
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    All-garnet magneto-optical photonic crystals2008Ingår i: Journal of the Magnetics Society of Japan, ISSN 1882-2924, Vol. 32, nr 2, s. 140-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We survey the properties of all-garnet magneto-optical (MO) heteroepitaxial film structures grown by pulsed laser deposition and rf-magnetron sputtering. 1D MO-photonic crystals (MOPCs) were composed of /4 garnet layers alternating highly gyrotropic B13Fe5O12 (BIG) and MO-passive rare earth gallium garnets. As designed, MOPCs' spectra exhibit optical stop band with the transmittance central peak caused by light localization in /2 thick BIG cavity. The first all-garnet BIG/YIG MOPC showed 140% enhancement of the Faraday rotation (FR) compared to a single layer BIG film [APL 84, 1438 (2004)]. Further improvement of MO-performance has been achieved due to the replacement of optically dense YIG by transparent Gd- (GGG), Sm- and novel La-Ga-garnets [APL 86, 141108 (2005); 87, 122504 (2005); 90, 191113 (2007); JAP 101, 053906 (2007)]. At the resonance wavelengths 750 (980) nm, specific FR F=-20.5 (-7.3) deg/m and MO-quality factor Q = 2 |F| /absorption = 66 (43.6) deg represent the highest MOPC performance achieved so far. Respectively, this is 470 (810) % and 31 (190)% enhancement compared to a single layer BIG. MO-remanence (latching capability) has been engineered in the series of BIG:GGG(n:m) superlattices. Regular alternating of lattice mismatched garnet layers impedes the nucleation of misfit dislocations, preserves a long range coherent compressive strain through the whole multilayer thickness thus results in a strong uniaxial magnetic anisotropy. 2.5 m thick BIG:GGG(3:2) film at 678 nm shows FR=1.4 deg, transmittance 82%, 92% squareness of magnetization loop, saturation and coercive fields as low as 56 and 25 Oe, respectively. Nanostructured garnets were used to build MO-visualizer and current driven MO-display [APL 88, 242504 (2006)].

  • 26.
    Grishin, Alexander
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Kim, Joo-Hyung
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergey
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Processing and on-wafer measurements of ferroelectric interdigitated tunable microwave capacitors2004Ingår i: Integration Of Advanced Micro-And Nanoelectronic Devices-Critical Issues And Solutions / [ed] Morais, J; Kumar, D; Houssa, M; Singh, RK; Landheer, D; Ramesh, R; Wallace, RM; Guha, S; Koinuma, H, 2004, Vol. 811, s. 307-312Konferensbidrag (Refereegranskat)
    Abstract [en]

    Na0.5K0.5NbO3 (NKN) and Pb(Zr0.53Ti0.47)O-3 (PZT) films have been grown by rf-magnetron sputtering and pulsed laser deposition techniques, correspondingly, on sapphire (Al2O3-0112, r-cut), YAlO3 + 1% Nd (Nd:YAlPO3-001), and quartz (Y+36degrees-cut) single crystal substrates. Interdigital capacitor (IDC) of coplanar waveguide (CPW) structures were defined by a standard lift off technique in a Au(0.5mum)/Cr(10nm) electrode electron beam evaporated on ferroelectric film surface. IDCs consisted of five pairs of fingers separated by 2 and 4 mum gap. On-wafer microwave characterization was performed using a workbench equipped with a coplanar probe station (Cascade Microtech) with G-S-G (Ground-Signal-Ground) Picoprobe, a network analyzer (Agilent Technologies E8364A) operating in 45 MHz to 40 GHz range and programmable power supply for de DUT (Device Under Test) biasing. Assumed equivalent circuit for the IDC/CPW structure contains planar capacitor under test C, the coplanar line with a complex impedance sigma and a parasitic capacitance C, between the signal and ground lines. The de-embedding technique has been employed to determine all six complex parameters C, sigma and C-p from S-parameter measurements performed for three different device structures: device, open and thru. NKN film interdigital capacitors on sapphire show superior performance in this microwave range: the frequency dispersion was as low as 18%, voltage tunability = 1 - C(40V)/C(0) (40 V, 200 kV/cm) about 14%, loss tangent similar to0.11, K-factor = tunability/tandelta from 131% @ 10 GHz: to 56% @ 40 GHz. The reliability of the de-embedding procedure is clearly proved by analysis of the frequency dependences of the parasitic capacitance and loss tangent as well as impedance of the coplanar line. Within the accuracy of experimental data and de-embedding calculations these values appear to be voltage independent: C-p similar to 70 fF, tan delta(p) changes from 0.07 @ 10 GHz to 0.15 @ 40 GHz; real and imaginary part of interconnect impedance increases with frequency from 0.16 Omega @ 10 GHz to 0.36 Omega @ 40 GHz and from 1.6 Omega @ 10 GHz to 5.84 Omega @ 40 GHz respectively.

  • 27.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik. Petrozavodsk State Univ, Petrozavodsk 185910, Russia.
    Khartsev, Sergey
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektronik.
    Waveguiding in All-Garnet Heteroepitaxial Magneto-Optical Photonic Crystals2019Ingår i: JETP Letters: Journal of Experimental And Theoretical Physics Letters, ISSN 0021-3640, E-ISSN 1090-6487, Vol. 109, nr 2, s. 83-86Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the properties of 1D all-garnet heteroepitaxial 21 layered magneto-optical photonic crystal designed and fabricated for the resonance wavelength 750 +/- 3 nm. It is composed of alternating magnetooptical-active Bi3Fe5O12 and transparent Sm3Ga5O12 quarter-wavelength layers radio frequency magnetron sputtered onto single crystalline Ca, Mg, Zr:Gd3Ga5O12(111) substrate. Edges of the band gap and resonant central peaks in transmission and Faraday rotation spectra experience significant (about 60 nm) "blueshift" when the angle of light incidence increases up to 70 degrees. Lower reflectance and strong enhancement of Faraday rotation of TE mode compared to the TM-polarized light testify a waveguiding of TE-mode within a resonant lambda/2 Bi3Fe5O12 cavity.

  • 28.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergey I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Luminescence in epitaxial Er-doped LiNbO3 films2012Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, nr 3, s. 419-421Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial Er-doped LiNbO3 films were pulsed-laser-deposited onto c-cut sapphire. Wavelength dispersion of the refractive index and the extinction coefficient was obtained by fitting the experimental transmittance spectrum to the Swanepoel formula and microscopic theory, which accounts for two resonance transitions in the electric dipole approximation. Strong room temperature luminescence was observed under 514.5 nm Ar-laser pumping. Two-lifetime (3.0 and 6.0 ms) luminescent decay is characteristic for the lasing I-4(13/2) -> I-4(15/2) transition in Er:LiNbO3 films.

  • 29.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Highly luminescent garnets for magneto-optical photonic crystals2009Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 95, nr 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We compare luminescent properties of several Er-doped garnets as building blocks in all-garnet heteroepitaxial magneto-optical photonic crystals. Pulsed laser deposited La3Ga5O12, Gd3Ga5O12, Y3Fe5O12, and rf-magnetron sputtered Bi3Fe5O12 were chosen to host Er3+ ions on dodecahedral lattice sites. Er substituents with the concentration of 0.5 at. % (0.1 garnet formula units) do not decrease giant Faraday rotation in Bi2.9Er0.1Fe5O12 garnet; meanwhile providing intense room temperature C-band photoluminescence (PL). Fe3+ ion works as a sensitizer for Er resulting in fivefold PL enhancement in iron garnets compared to gallium ones. PL lifetime in gallium garnets is in millisecond range reaching almost 6 ms in Gd2.9Er0.1Ga5O12. We conclude Er substitution in gallium and iron garnet layers used both as Bragg mirrors and microcavities promises magneto-optical photonic crystals to become an active lasing medium.

  • 30.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Bonetti, S.
    Low field driven latching-type Bi3Fe5O12/Gd3Ga5O12 magneto-optical display2006Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 88, nr 24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Series of heteroepitaxial all-garnet magneto-optical (MO) Bi3Fe5O12n/Gd3Ga5O12m /BIG(n)/GGG(m), n= 1, 2, 3, 4, 5 and m=1 and 2 are the numbers of unit cells) nanostructured multilayers have been sintered by pulsed laser deposition technique. Processing parameters and structure of grown films have been optimized to obtain perpendicular magnetic anisotropy and square hysteresis loop with low coercive and saturation magnetic fields. Regular alternating of lattice mismatched BIG and GGG atomic layers inhibited nucleation of misfit dislocations; thus a long range coherent compressive strain was preserved through the whole thickness of BIG(n)/GGG(m) multilayer stack. 2.5 mu m thick BIG(3)/GGG(2) sample (1200 BIG and 800 GGG unit cells) at lambda= 678 nm shows MO Faraday rotation Phi(F)= +/- 1.4 degrees, transmittance of 82%, attenuation alpha=3400 dB/cm, squareness of magnetization loop (remnant-to-saturation magnetizations ratio) as high as 92%, and saturation and coercive fields as low as 56 and 25 Oe, respectively. MO remanence (latching capability) enables application of nanostructured garnet as a magnetic relief replicator/visualizer and as a material for low power consuming displays.

  • 31.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Green and blue magneto-optical photonic crystals2012Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 9, s. 3647-3650Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals (MOPCs) were pulsed laser deposited to operate at 550 and 470 nm wavelength. We explored the concept of blue shift of the optical absorption edge of ferric ions by substituting Fe with Ga on the tetrahedral sites as well as Bi and Y, respectively, with Ca and Ce at the dodecahedral coordinated positions. 17-layered [Y2Ce1Fe5O12/Gd3Ga5O12] MOPC with a total thickness of 968 nm demonstrates superior magneto-optical performance: Faraday rotation theta(Fmax) = + 2.0 degrees and transmittance as high as 0.35 at the resonance wavelength of 470 nm.

  • 32.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Luminescent Magneto-Optical Photonic Crystals2012Ingår i: ASIA-PACIFIC INTERDISCIPLINARY RESEARCH CONFERENCE 2011 (AP-IRC 2011), 2012, s. 012007-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    We compare luminescent properties of several Er-doped garnet films as building blocks in all-garnet heteroepitaxial magneto-optical photonic crystals: La3Ga5O12, Gd3Ga5O12, Y3Fe5O12, Bi3Fe5O12, and Bi2.97Er0.03Fe4Al0.5Ga0.5O12. Er substituents on the dodecahedral lattice sites do not decrease giant Faraday rotation in Bi3Fe5O12 garnet; meanwhile providing intense room temperature C-band photoluminescence (PL). Fe3+ ion works as a sensitizer for Er resulting in fivefold PL enhancement in iron garnets compared to gallium ones. PL lifetime in gallium garnets is in millisecond range reaching 6 ms in Gd2.9Er0.1Ga5O12. The first luminescent one-dimensional heteroepitaxial all-garnet magneto-optical (MO) photonic crystal was composed from diamagnetic Sm3Ga5O12 and MO-active Bi2.97Er0.03Fe4Al0.5Ga0.5O12 garnet layers by rf-magnetron sputtering on Gd3Ga5O12(111) substrate. Substitution of ferric ions by aluminum and gallium improved transparency and induced perpendicular anisotropy in pure Bi3Fe5O12. Photonic crystals owned a record high magneto-optical quality and a latching type (magnetic remnant) Faraday rotation (FR). At the resonance wavelength 775 nm, specific FR theta(F) = -14.1 deg/mu m and MO-quality factor Q = 99.3 deg represent the highest MO performance achieved so far. Long-lived near-IR luminescence in Er substituted gallium and iron garnet layers used both as Bragg mirrors and microcavities promises magneto-optical photonic crystals to become an active lasing medium.

  • 33.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Kawasaki, H.
    980 nm Bi3Fe5O12/Sm3Ga5O12 magneto-optical photonic crystal2007Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, nr 19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Heteroepitaxial all-garnet magneto-optical photonic crystal (MOPC) was fabricated to enhance Faraday rotation at 980 nm. MOPC was composed of alternating MO-active Bi3Fe5O12 and transparent Sm3Ga5O12 quarter-wavelength layers grown by rf-magnetron sputtering on Ca,Mg,Zr:Gd3Ga5O12(111) single crystal substrate. High MO performance at the resonance wavelength lambda=980 nm, specific Faraday rotation theta(F)=-7.3 degrees/mu m, absorption coefficient alpha=3350 cm(-1), and MO figure of merit Q=2 parallel to theta(F)parallel to/alpha=43.6 degrees demonstrates feasibility to use bismuth iron garnet MOPCs for application in pump laser diodes, optical amplifiers, modulators, and sensors.

  • 34.
    Grishin, Alexander M.
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Kim, Joo-Hyung
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Lu, J.
    Epitaxial colossal magnetoresistive/ferroelectric heterostructures on Si2004Ingår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 67, s. 69-76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on processing and properties of La-0.67(SrCa)(0.33)MnO3 (LSCMO) films grown by pulsed laser deposition technique on Si(001) substrates buffered with Bi4Ti3O12/CeO2/YSZ heteroepitaxial layers. X-ray diffraction shows cube-on-cube growth of epitaxial Bi4Ti3O12/CeO2/YSZ/Si heterostructure whereas the LSCMO layer grows in the diagonal-on-side manner onto the Bi4Ti3O12 (BTO) template. High resolution TEM images demonstrate sharp interfaces between the buffer layers and LSCMO film as well as rare misfit dislocations on the CeO2/YSZ interface. LSCMO film processing conditions have been optimized to get maximum temperature coefficient of resistivity TCR = 4.4% K-1 and colossal magnetoresistance (CMR) Deltarho/rho similar to 2.9% kOe(-1) @ 294 K. Almost ultimate CMR performance at room temperature has been achieved due to successive improvement of c-axis orientation of layers: full widths at half-maximum (FWHM) = 0.65, 0.58, 0.65, 1.13 and 0.18 degrees in LSCMO/BTO/CeO2/YSZ/Si stack, respectively. Characterization of electrical noise in CMR film yields Noise Equivalent Temperature Difference (NETD) as low as 1.2 muK/rootHz @ 30 Hz and 294 K.

  • 35.
    Grishin, Alexander M.
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Kim, Joo-Hyung
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Lu, J.
    Epitaxial La-0.67(Sr,Ca)(0.33)MnO3 films on Si for IR bolometer applications2004Ingår i: Integration Of Advanced Micro-And Nanoelectronic Devices-Critical Issues And Solutions / [ed] Morais, J; Kumar, D; Houssa, M; Singh, RK; Landheer, D; Ramesh, R; Wallace, RM; Guha, S; Koinuma, H, 2004, Vol. 811, s. 405-410Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report on processing and properties of La-0.67(Sr,Ca)(0.33)MnO3 (LSCMO) films grown by pulsed laser deposition technique on Si(001) substrates buffered with Bi4Ti3O12/CeO2/YSZ heteroepitaxial layers. X-ray diffraction shows cube-on-cube growth of epitaxial Bi4Ti3O12/CeO2/YSZ/Si heterostructure whereas the LSCMO layer grows in the "diagonal-on-side" manner onto the Bi4Ti3O12 (BTO) template. High resolution TEM images demonstrate sharp interfaces between the buffer layers and LSCMO film as well as rare misfit dislocations on the CeO2/YSZ interface. LSCMO film processing conditions have been optimized to get maximum temperature coefficient of resistivity TCR = 4.4%K-1 and colossal magnetoresistance (CMR) Deltarho/rho similar to 2.9%kOe(-1) @ 294K. Almost ultimate CMR performance at room temperature has been achieved due to successive improvement of c-axis orientation of layers: full widths at half-maximum (FWHM) 0.65, 0.58, 0.65, 1.13 and 0.18 degrees in LSCMO/BTO/CeO2/YSZ/Si stack, respectively. Characterization of electrical noise in CMR film yields noise equivalent temperature difference (NETD) as low as 1.2 muK/rootHz @ 30Hz and 294K.

  • 36.
    Grishin, Alexander M.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Vanin, E. V.
    Tarasenko, O. V.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Johansson, P.
    Strong broad C-band room-temperature photoluminescence in amorphous Er2O3 film2006Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photoluminescence with the bandwidth of 45 nm (1523-1568 nm at the level of 3 dB) was observed in amorphous Er2O3 films grown on quartz substrate by pulsed laser ablation of erbium oxide stoichiometric target. Optical transmission spectrum has been fitted to Swanepoel formula [J. Phys. E 16, 1214 (1983)] to determine dispersion of refractive index and to extract resonance absorption peaks at 980 and 1535 nm. The maximum gain coefficient as high as 800 dB/cm at 1535 nm was estimated using McCumber theory and experimental spectrum of the resonance absorption. For 5 mm long waveguide amplifier with erbium doping confinement factor of 0.1, the theory predicts the spectral gain of 18 dB with 1.2 dB peak-to-peak flatness in the bandwidth of 31 nm (1532-1563 nm) when 73% of Er3+ ions are excited from the ground state to the I-4(3/2) laser level. Strong broadband photoluminescence at room temperature and inherently flat spectral gain promise Er2O3 films for ultrashort high-gain optical waveguide amplifiers and integrated light circuits.

  • 37.
    Grishin, Michael A.
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Karlsson, Ulf O.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    High performance films of binary system SrTiO3-PbZr0.52Ti0.48O3 on sapphire2001Ingår i: Integrated Ferroelectrics, ISSN 1058-4587, E-ISSN 1607-8489, Vol. 39, nr 1-4, s. 351-358Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Continuous series of solid solutions x.SrTiO3-(1-x).PbZr0.52Ti0.48O3 (SPZT) have been grown by pulsed laser deposition technique onto La0.7Sr0.3CoO3/Al2O3(01 (1) under bar2) single crystal. Films properties have been characterized in Au/SPZT/La0.7Sr0.3CoO3(LSCO)/Al2O3 vertical capacitive cell. X-ray diffraction shows SPZT/LSCO bilayer grows in strict epitaxial relationship with sapphire substrate: (001) SPZT parallel to (001) LSCO parallel to (01 (1) under bar2) Al2O3; [010] SPZT parallel to [010] LSCO parallel to [421] Al2O3. LSCO layer was found to be tensile strained, while SPZT film experiences tetragonal distortions c/a -1 approximate to 0.86% which are much lower than 2.73% in pure PZT ceramics. Curie temperature in SPZT film has been tailored continuously in the explored temperature range 77 K to 400 K by controlling SrTiO3:PZT ratio. Processing parameters have been optimized to get the highest tunability factor K = epsilon'(0) - epsilon'(V)/epsilon'(0) x 1/tandelta . SrTiO3:PZT=83:17 film exhibits superior properties: at I kHz maximum dielectric perinittivity and minimum loss tandelta were found to be 870 and 0.005, respectively; while K-factor exceeds value of 60 in the temperature range 280 to 350 degreesC reaching the maximum value of 64 at 325 degreesC. SPZT films can withstand prolonged pre-breakdown electric field and has resistivity as high as 3.5 10(12) Omega cm at 186 kV/cm.

  • 38. Haidar, M.
    et al.
    Durrenfeld, P.
    Ranjbar, M.
    Balinsky, M.
    Fazlali, M.
    Dvornik, M.
    Dumas, R. K.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Åkerman, Johan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF. University of Gothenburg, Sweden.
    Controlling Gilbert damping in a YIG film using nonlocal spin currents2016Ingår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 94, nr 18, artikel-id 180409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We demonstrate the control of Gilbert damping in 65-nm-thick yttrium iron garnet (YIG) films using a spin-polarized current generated by a direct current through a nanocontact, spin filtered by a thin Co layer. The magnetodynamics of both the YIG and the Co layers can be excited by a pulse-modulated microwave current injected through the nanocontact and the response detected as a lock-in amplified voltage over the device. The spectra show three clear peaks, two associated with the ferromagnetic resonance (FMR) in each layer, and an additional Co mode with a higher wave vector proportional to the inverse of the nanocontact diameter. By varying the sign and magnitude of the direct nanocontact current, we can either increase or decrease the linewidth of the YIG FMR peak consistent with additional positive or negative damping being exerted by the nonlocal spin current injected into the YIG film. Our nanocontact approach thus offers an alternative route in the search for auto-oscillations in YIG films.

  • 39. Haidar, M.
    et al.
    Ranjbar, M.
    Balinsky, M.
    Dumas, R. K.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Åkerman, Johan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Materialfysik, MF. University of Gothenburg, Sweden.
    Thickness- and temperature-dependent magnetodynamic properties of yttrium iron garnet thin films2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 17, artikel-id 17D119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The magnetodynamical properties of nanometer-thick yttrium iron garnet films are studied using ferromagnetic resonance as a function of temperature. The films were grown on gadolinium gallium garnet substrates by pulsed laser deposition. First, we found that the damping coefficient increases as the temperature increases for different film thicknesses. Second, we found two different dependencies of the damping on film thickness: at room temperature, the damping coefficient increases as the film thickness decreases, while at T = 8 K, we find the damping to depend only weakly on the thickness. We attribute this behavior to an enhancement of the relaxation of the magnetization by impurities or defects at the surfaces.

  • 40. Hollmark, M.
    et al.
    Tkatch, V. I.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Processing and properties of soft magnetic Fe40Co40P14B6 amorphous alloy2001Ingår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 37, nr 4, s. 2278-2280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Fe40Co40P14B6 metallic alloy has been prepared in a glassy state by a melt-spinning process. The 15-25 mum thick as-quenched, ribbons have superior soft magnetic properties compared with those of well-known Fe40Ni40P14B6 glass: the saturation magnetization is about 1.45 T, coercive field 4.0 A/m @ 0.1 Hz, incremental magnetic permeability mu (max) similar to 90 000 @ 60 Hz and Curie temperature above 700 K. The crystallization temperature, determined by differential scanning calorimeter, is approximately 60 K higher than that for FeNi-based alloy, indicating the enhanced thermal stability of FeCo-glass.

  • 41.
    Jalalian, Abolfazl
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Kavrik, Mahmut Sami
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Khartsev, Sergiy I.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Ferromagnetic resonance in Y(3)Fe(5)O(12) nanofibers2011Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, nr 10, s. 102501-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Continuous bead-free polycrystalline yttrium iron garnet (YIG) nanofibers 100 mu m long and 50-100 nm in diameter were sintered by sol-gel calcination assisted electrospinning. Room temperature ferromagnetism in YIG fibers is indicated by a well formed M-H hysteresis loop with about 70% of remnant magnetization to the saturated value reached at 150 Oe. Broad band microwave spectroscopy revealed strong asymmetry of ferromagnetic resonance lines that conforms to a three orders of magnitude shape aspect ratio of YIG nanofibers.

  • 42.
    Jalali-Roudsar, Amir A.
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Denysenkov, Vasyl
    KTH, Tidigare Institutioner                               , Fysik.
    Khartsev, Sergey
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Adachi, N.
    Okuda, T.
    Microwave and magneto-optic properties of pulsed laser deposited bismuth iron garnet films2001Ingår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 37, nr 4, s. 2454-2456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     We report on processing and comparative characterization of epitaxial Bi3Fe5O12 (BIG) films grown by pulsed laser ablation of a precursor oxide target onto (NdGd)(3)(ScGa)(5)O-12 [NGSGG(111)] and Gd-3 (ScGa)(5)O-12 (GSGG(001)] single crystals. Comprehensive X-ray diffraction analyses reveal the epitaxial quality of the BIG films: they are single phase, exclusively (111) and (001) oriented with less than 0.4 degrees and 0.06 degrees of the full width at half maximum of the rocking curve of main texture Bragg reflection [(111) for NGSGG and (001) for GSGG substrate, respectively]. The films are strongly in-plane textured with cube-on-cube film-to-substrate epitaxial relationship. VSM and ferromagnetic resonance measurements revealed in-plane magnetization in BIG/GSGG(001) film, while the BIG/NGSGG(111) film was found to have perpendicular magnetization. For BIG(001) and (111) films the saturation magnetization 4 piM(s) was found to be 1400 and 1200 Gs; the Faraday rotation at 635 nm was -7.8 and -6.7 deg/mum; the constant of uniaxial magnetic anisotropy was K-u* = -8.70 X 10(4) and +1.16 x 10(4) erg/cm(3); the constant of cubic magnetic anisotropy K-1 = -3.6 x 10(3) and -7.14 x 10(3) erg/cm(3). High Faraday rotation and low coercive field (less than or equal to 40 Oe) of BIG/GSGG(001) films show promise for their use in integrated magneto-optic applications.

  • 43.
    Jalali-Roudsar, Amir Abbas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Denysenkov, V.P.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Determination of magnetic anisotropy constants for magnetic garnet epitaxial films using ferromagnetic resonance2005Ingår i: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 288, s. 15-21Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The constants of magnetocrystalline anisotropy K-l and uniaxial anisotropy K-u are determined precisely by using ferromagnetic resonance (FMR) and a fitting procedure oil a (1 1 1) yttrium iron garnet (YIG) film made by pulsed laser deposition (PLD) technique. By applying a magnetic field in the azimuthal orientation we introduce measurement in a geometry which yields the anisotropy constants with a high accuracy. The new technique is compared with the previous analysis employing characteristic plane measurements. The new geometry yields at least 15% better accuracy in determining constant K, than by the previous method with FMR.

  • 44.
    Johansson, Petter
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik.
    Comparison of Bi3Fe5O12 film giant Faraday rotators grown on (111) and (001) Gd3Ga5O12 single crystals2006Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 515, nr 2, s. 477-480Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bismuth iron garnet (Bi3Fe5O12, BIG) epitaxial thin films were grown on single crystal (Gd3Ga5O12, GGG) (111) and (001) substrates by rf-magnetron sputtering technique. Processing parameters have been optimized to obtain high deposition rate (2.74 mu m/h) and the surface rms roughness less than 10 nm. X-ray diffraction reveals films epitaxial quality: exclusive (111) or (00 1) orientation with narrow rocking curves and strong in-plane texture. Films possess low optical loss and magneto-optical Faraday rotation (FR) as high as 5 deg/mu m at 677 nm wavelength. Comparative analysis of films grown on (111) and (001) substrates clearly shows significant superiority of BIG/GGG(001) film. For this film, the coercive field similar to 100 Oe appears to be 2.5 times lower while the optical transmission to be 10% higher than that for BIG/GGG(111) film. Enhanced magneto-optical performance of BIG/GGG(001) films relies upon better accommodation of the film-to-substrate mismatch strain through the tetragonal BIG lattice distortions compared to the rhombohedral one in BIG/GGG(111) films.

  • 45. Kahl, S.
    et al.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Kawano, K.
    Abell, J. S.
    Bi3Fe5O12 thin film visualizer2001Ingår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 37, nr 4, s. 2457-2459Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Micrometer thick Bi-3 Fe-5 O-1.2 (BIG)(001) films were grown onto Gd-3(ScGa)(5)O-12(001) single crystals by the pulsed laser deposition technique. The films are of epitaxial quality with a lattice constant of 1.263 nm. Narrow x-ray rocking curves (full width at half maximum: 0.06 deg) and narrow ferromagnetic resonance lines (widths of 25 Oe) indicate good crystalline quality and magnetic performance. The films possess in-plane magnetization, Faraday rotation as high as -7.8 deg/mum at 630 nm wavelength, and the magnetization M-H curves are linear in the field range from -1.6 kOe to +1.6 kOe. The magneto-optical (MO) properties are almost temperature independent between 5 K and 200 K. This enables the use of thin BIG films as visualizers of magnetic fluxes in high-T-c superconductors. Magnetic fluxes have been visualized in YBa2Cu3O7-infinity, (YBCO) ceramics with an artificial grain boundary. The sensitivity expressed as Faraday rotation angle (per film thickness) per magnetic field unit was found to be 4.9 deg/(kOe . mum) in a 730 nm thick BIG film.

  • 46. Kahl, S.
    et al.
    Khartsev, Sergiy
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Grishin, Alexander M.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Kawano, K.
    Kong, G.
    Chakalov, R. A.
    Abell, J. S.
    Structure, microstructure, and magneto-optical properties of laser deposited Bi3Fe5O12/Gd3Ga5O12(111) films2002Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 91, nr 12, s. 9556-9560Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bi3Fe5O12 films were deposited onto single crystal Gd3Ga5O12(111) substrates by pulsed laser deposition. X-ray diffraction patterns and cross sectional transmission electron micrographs show epitaxial film growth and a flat interface between the film and substrate. However, there are small inclusions at the interface and a network of cracks is observed by optical microscope. The refractive index is 3.4 at 800 nm wavelength. The optical transmission is low below 540 nm but increases to 90% for a 1.8 mum thick film at 850 nm. The magneto-optical Faraday rotation is high, with a peak value of -24 deg/mum at 560 nm. The angle of Faraday ellipticity reaches a maximum value of 15 deg/mum at 545 nm.

  • 47.
    Kawasaki, Hiroharu
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Ohshima, T.
    Yagyu, Y.
    Suda, Y.
    Khartsev, Sergiy
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Grishin, Alex
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    TiO2/TiN/TiO2 heat mirrors by laser ablation of single TiN target2008Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100, nr 1, s. 012038-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titanium oxide (TiO2 ) and titanium nitride (TiN) multilayered films grown by pulsed laser deposition (PLD) technique have been tested as a heat mirror, which have a high transmittance in the visible region and a high reflectance in the infrared. Three layer TiO2 /TiN/TiO2 heat mirrors were grown on Corning glass substrates ablating single TiN target. Switching of TiO2 -to-TiN layers composition was achieved by changing gas atmosphere (oxygen-to-nitrogen). Grown TiO2 /TiN/TiO2 heat mirrors are highly transparent in visible (above 60% at 525nm), opaque in infrared (10% at 2600nm) and in the range from 400 nm to 2600 nm they possess almost the same properties as films prepared using two targets: TiO2 and TiN. XPS confirms similarity of chemical composition of multilayered TiO2 /TiN films prepared by single TiN and two TiO2 and TiN targets techniques. Furthermore, multifunctional self cleaning properties of TiO2 /TiN heat mirrors are expected through the precise control of the composition of the top TiO2 layer operating as a photocatalyst.

  • 48.
    Khartsev, Sergey I.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Grishin, Alexander M.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    High performance latching-type luminescent magneto-optical photonic crystals2011Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 36, nr 15, s. 2806-2808Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the properties of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals (MOPCs) composed of alternating quarter-wavelength layers of diamagnetic Sm(3)Ga(5)O(12) and MO-active Bi(2.97)Er(0.03)Al(0.5)Ga(0.5)O(12) garnets rf-magnetron sputtered on Gd(3)Ga(5)O(12)(111) substrate. Substitution of ferric ions by aluminum and gallium improved transparency and induced perpendicular anisotropy in pure bismuth iron garnet. As a result, photonic crystals owned a record high magneto-optical quality and a latching-type (magnetic remnant) Faraday rotation (FR). At the resonance wavelengths 775(640)nm, a specific FR theta(F) - -14.1(14.8) deg/mu m and MO-quality factor Q = 99.3(46.2) deg represent the highest MOPC performance achieved so far.

  • 49.
    Khartsev, Sergiy
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Materialfysik, MF.
    Grishin, A. M.
    High performance Bi3Fe5O12/Sm3Ga5O12 (m) magneto-optical photonic crystals2007Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the properties of one-dimensional heteroepitaxial all-garnet magneto-optical (MO) photonic crystals (MOPCs) composed of alternating MO-active Bi3Fe5O12 (BIG) and transparent Sm3Ga5O12 (SGG) quarter-wavelength layers grown by rf-magnetron sputtering on Ca,Mg,Zr:Gd3Ga5O12(111) and Gd3Sc2Ga3O12(001) crystals. MOPCs' spectra, as designed, exhibit a stop band structure and a band gap with the transmittance central peak at 750 nm caused by light localization in the half-wavelength BIG cavity. A series of MOPCs with different numbers of [BIG/SSG](m) reflectors (m=4, 5, and 6) has been fabricated to optimize the specific Faraday rotation theta(F) (deg/mu m) and MO-quality factor Q(deg)=2 parallel to theta(F)parallel to/absorption coefficient. A close BIG-to-SGG lattice match enabled significant improvement of [Bi3Fe5O12/Sm3Ga5O12](m) properties compared to previously reported [Bi3Fe5O12/Y3Fe5O12](m) [S. Kahl and A. M. Grishin, Appl. Phys. Lett. 84, 1438 (2004)] and [Bi3Fe5O12/Gd3Ga5O12](m) [S. I. Khartsev and A. M. Grishin, Alexander M.

  • 50.
    Khartsev, Sergiy
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    Grishin, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Teoretisk fysik, Kondenserade materiens teori.
    New garnet films for magneto-optical photonic crystals2005Ingår i: Magneto-Optical Materials For Photonics and Recording / [ed] Ando, K; Challener, W; Gambino, R; Levy, M, WARRENDALE: MATERIALS RESEARCH SOCIETY , 2005, Vol. 834, s. 47-52Konferensbidrag (Refereegranskat)
    Abstract [en]

    Epitaxial La3Ga5O12 (LGG) garnet films and Bi3Fe5O12/La3Ga5O12 (BIG/LGG) heteroepitaxial structures have been synthesized on Gd3Ga5O12(GGG,111) single crystal. LGG films were grown by Pulsed Laser Deposition (PLD) technique whereas rf-magnetron sputtering was used to grow BIG films. We demonstrate LGG is a promising material to be integrated with a giant Faraday rotator Bi3Fe5O12 in magneto-optical photonic crystals. LGG has a lattice constant 12.772 angstrom that is bigger than that in GGG (12.384 angstrom) and closer to that in BIG (12.626 angstrom). Heteroepitaxial Bi3Fe5O12(2 mu m)/La3Ga5O12(300nm) structures grown on the GGG(111) single crystal show the Faraday rotation as high as 5.74 deg/mu m compared to 5.46 deg/mu m in BIG/GGG at lambda = 655 nm. Fitting LGG reflectivity spectra to Fresnel formulas yields LGG refractive index n = 1.981 compared to 1.963 in GGG at 655 nm. Dispersion of LGG refraction index follows Sellmeier formula n(2) = 1 + 2.78/[1 - (138nm/lambda)(2)] in the range from 400 nm to 1000 nm.

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