Pulsed laser deposited Y3Fe5O12 films: Nature of magnetic anisotropy I
2009 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, no 12Article in journal (Refereed) Published
Recently we sintered by pulsed laser deposition (PLD) technique the epitaxial Fe-deficient yttrium iron garnet (YIG) films with ferromagnetic resonance (FMR) linewidth as narrow as 0.9 Oe, the uniaxial anisotropy as high as H-u=-880 Oe, and demonstrated them feasible for magnetostatic waves band pass filter application [Manuilov , J. Appl. Phys. 105, 033917 (2009)]. Here we explore the origin of unusually high noncubic magnetic anisotropy. Using the angular resolved FMR spectroscopy we found that in addition to strong uniaxial anisotropy, cubic magnetic anisotropy experienced almost fivefold reduction compared to standard YIG grown by liquid phase epitaxy. Molecular field theory was employed to calculate saturation magnetization 4 pi M-s, cubic magnetocrystalline K-1, and uniaxial anisotropy K-u in garnets with Fe vacancies. The modeling utilizes crystal field parameters that we revealed from earlier published experimental data on diamagnetic ion substituted Y3Fe5O12 and Fe-substituted isomorphous diamagnetic garnets. Consistent single ion anisotropy crystal field theory perfectly fits experimentally observed high saturation magnetization, reduction in cubic, and appearance of strong uniaxial anisotropy in PLD-grown Fe-deficient YIG films. The redistribution of Fe vacancies between different magnetic sublattices was quantified and confirmed that in YIG(111) films ferric ions preferentially leave vacant octahedrally coordinated sites. Simulation of growth induced anisotropy proves the ordering of Fe3+ vacancies within octahedral sites. At equal number of available ferric ions and vacancies, the latter populate the octahedrons with distortion axis perpendicular to the film surface with the probability equal to 0.67. Deformation blockage of octahedral complexes with distortion axes directed along the film surface reduces this probability down to 0.14.
Place, publisher, year, edition, pages
2009. Vol. 106, no 12
crystal field interactions, diamagnetic materials, ferrites, ferromagnetic resonance, garnets, magnetic anisotropy, magnetic, epitaxial layers, pulsed laser deposition, vacancies (crystal), yttrium, compounds, yttrium-iron-garnet, growth-induced anisotropy, ferromagnetic-resonance, paramagnetic-resonance, yig-films
IdentifiersURN: urn:nbn:se:kth:diva-19087DOI: 10.1063/1.3272731ISI: 000273216500064ScopusID: 2-s2.0-73849083000OAI: oai:DiVA.org:kth-19087DiVA: diva2:337134
QC 201005252010-08-052010-08-052011-11-22Bibliographically approved