Magnetic anisotropy and magnetic anneal in silicon-doped yttrium iron garnet

Abstract

Measurements are reported on the resonance field and linewidth of ferromagnetic resonance for specimens of silicon-doped yttrium iron garnet with composition Y3Fe5-xSixO12 where x=0.006, 0.020, 0.034 and 0.08. The temperature range covered is 2K to 300 K; the measurement frequencies are 9.415 GHz and 30.05 GHz. Magnetic anneal effects are studied at low temperatures. It is concluded that valence exchange between Fe2+ and Fe3+ on octahedral sites requires much more than 10-10 s for thermal equilibration throughout the temperature range, hence the resonant magnetization experiences the magnetocrystalline anisotropy appropriate to a 'frozen' Fe2+ population.