Identification of a new source of magnon relaxation in interface between epitaxial iron garnet ferrite films and GGG substrate

• Published in: Materials research bulletin 2022-05, Vol.149, p.111691, Article 111691
• Main Authors: Kuzmichev, A.N., Belotelov, V.I., Bunkov, Y.M., Vetoshko, P.M., Popov, A.I., Berzhansky, V.N., Shaposhnikov, A.N., Sabdenov, Ch.K., Koshelev, A.V., Fedorenko, A.A.
• Format: Article
• Language: English
• Subjects: Epitaxial films; Ferrite-garnet; FMR; Low temperatures; Magnetic dissipation; YIG
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2021.111691

•Strong increase in the relaxation rate was investigated at temperatures below 100 K in epitaxial iron garnet films.•Compound with Gd3+ ions is formed in the transition layer, which has a considerable magnetic moment.•Unlike other relaxation mechanisms, this one cannot be compensated for.•For further improvement we suggest to use substrates without strong paramagnetic ions like a Y3Ga3Sc2O12 substrate. [Display omitted] We have investigated the intermediate layer between the gallium-gadolinium garnet substrate and the yttrium-iron garnet epitaxial film. This interlayer is characterized by a large magnetic moment at low temperatures, which leads to an anomalous dependence of the susceptibility and a shift in the magnetic resonance frequency upon cooling. This shift is much larger than might be expected due to magnetization anisotropy, substrate paramagnetic ions, and magnetostriction. We found that this interlayer plays a major role in magnetic relaxation processes in the temperature range below 50 K.