Change search
ReferencesLink to record
Permanent link

Direct link
Broadband Ferromagnetic Resonance Spectrometer: Instrument and Applications
KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
2003 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This thesis compiles results of research in two mutuallydependent parts: 1) development of ferromagnetic resonance(FMR) spectrometer to study microwave properties offerromagnetic materials, and 2) characterization of new irongarnets: pulsed laser deposited Y3Fe5O12and Bi3Fe5O12films and Ce:Y3Fe5O12single crystal.

First part describes a novelBroadbandFMRSpectrometerdesigned to characterize thin ferromagneticfilms. The spectrometer uses two probeheads: one is the X-bandmicrowave reflection cavity for room temperature measurementsand the in-cryostat microstrip line probe to perform FMRexperiments in the frequency range from 50 MHz to 40 GHz. Veryuniform and stable magnetic field up to 2.4 T, temperatures 4 Kto 420 K, and continuous frequency scan performed byHP8722Dvector network analyzer provide various modes ofoperation. Both probeheads are equipped with two-circlegoniometers to ensure accurate study of magneticanisotropy.

The spectrometer was used to make express-analysis ofquality thus to optimize processing parameters of epitaxialiron garnet films grown by pulsed laser deposition (PLD).Comprehensive study of uniaxial and cubic magnetocrystallineanisotropy has been performed for Ce:Y3Fe5O12bulk crystal as well as for Y3Fe5O12and Bi3Fe5O12films grown on different substrates by PLD andreactive ion beam sputtering techniques. BroadbandFMR-spectroscopy revealed difference in spectra of domain wallresonances: instead of“soft”spin modes in filmsgrown by liquid phase epitaxy, PLD-made films show“diffuse”transformation of domains near thesaturation field. This effect indicates non-uniformity ofsaturation magnetization and field of uniaxial anisotropy inPLD-iron garnets. Spin wave resonances in comparison withuniform FMR have been studied to evaluate“localquality”of ferromagnetic films. The resonance field andFMR linewidth behavior were studied at various crystallographicdirections determined by X-ray diffraction.

FMR was used to choose PLD-made YIG films with low losses atmicrowave frequencies and to build magnetostatic surface wavesmicrowave bandpass filter. The filter was designed as a planarfilm structure with a microstrip line for transducers. It is afirst demonstration of feasibility to introduce PLD processingtechnique to magnetostatic wave technology.

Magneto-optical study of Ce:Y3Fe5O12single crystal complements results ofFMR-spectroscopy of new garnets.

Keywords:ferrites, thin films, ferromagnetic resonance,microwaves, FMR spectrometer, magnetic anisotropy,magnetostatic waves.

Place, publisher, year, edition, pages
Kista: Mikroelektronik och informationsteknik , 2003. , vi, 88 p.
Keyword [en]
ferrites, thin films, ferromagnetic resonance, microwaves, FMR spectrometer, magnetic anisotropy, magnetostatic waves
URN: urn:nbn:se:kth:diva-3602ISBN: Trita-FYS. 5290OAI: diva2:9431
Public defence
NR 20140805Available from: 2003-09-16 Created: 2003-09-16Bibliographically approved

Open Access in DiVA

fulltext(9305 kB)917 downloads
File information
File name FULLTEXT01.pdfFile size 9305 kBChecksum MD5
Type fulltextMimetype application/pdf

By organisation
Microelectronics and Information Technology, IMIT

Search outside of DiVA

GoogleGoogle Scholar
Total: 917 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 585 hits
ReferencesLink to record
Permanent link

Direct link