강자성공명 현상을 이용한 YIG의 자기적 특성 연구

다국어 초록 (Multilingual Abstract)

Stoichiometric and nonstoichiometric Y_(3-x)Fe_(5+x)O₁₂ polycrystalline samples (x=0.00, 0.05, 0.10, 0.30, -0.05, -0.10, -0.30) were prepared by solid state reaction method. The magnetic properties of the sample were investigated by FMR (ferromagnetic resonance) technique at microwave frequency 5.11 ㎓ (G-band) and 23.39 ㎓ (K-band) respectively. The spectroscopic splitting factor g were estimated to be 2.04~2.35 from the derivative absorption lines. As the samples became yttrium (Y³+) excess and iron (Fe³+) excess, Magnetizations were decreased. But resonance linewidth were increased. To investigate the anisotropy, the angular dependence of resonance magnetic fields were measured. Angular dependence of effective magnetizations were measured by FMR from 77 K to 300 K at K-band microwave frequency (23.39 ㎓) and the saturation magnetizations were measured by VSM. The Bloch coefficients B and C were determined by fitting. Meff(0) was obtained by the extrapolation from 80 K. From this result, the spin wave stiffness constant D (about 162~206 eVŲ)and average square range of exchange interaction <r²> (about 5.84~12.13 Ų) were determined.