Relaxation behaviors of the bismuth-substituted yttrium iron garnet in the microwave range

摘要

The spin damping behavior of the bismuth-substituted yttrium iron garnets (Bi_xY_(3-x)Fe_5O_(12)) prepared by the coprecipitation process was investigated using the ferromagnetic resonant (FMR) in this study. By analyzing the FMR responses, the spin damping coefficient of the x = 0.25 -1.25 in polycrystalline Bi:YIG (yttrium aluminum garnet) samples was obtained from the 3 dB linewidth of their FMR spectra. The data demonstrated that the damping coefficient started from 3.21 × 10~(-3) for x=0.25 and went to its minimum value of 0.31 × 10~(-3) for x=0.75. However, the damping coefficient enhanced to 8.55× 10~(-3) with increasing of the bismuth concentration to x=1.25. The results revealed that the spin damping behavior of the Bi:YIG garnets was strongly dependent on a YFeO_3 (111) phase.