有磁和无磁状态下YIG和YAG晶体高压下的声速和衰减

 YAG晶体是一种无磁石榴石,YIG晶体是铁磁石石榴石。通过对YAG和YIG晶体在高压加磁场和不加磁场条件下,研究铁磁石榴石和无磁石榴石晶体的超声行为。采用“回波重合法”测量声速,通过比较回波的幅度进行衰减的测量。我们发现,不存在磁场时,有磁石榴石和无磁石榴石在高压条件下声速和声衰减有类似的变化行为。我们也发现,无论有无高压,在YAG晶体中不存在磁声相互作用,而在YIG晶体中,则存在磁声相互作用。

THE SOUND VELOCITY AND THE ATTENUATION OF YIG AND YAG CRYSTAL UNDER PRESSURE WITH AND WITHOUT AN EXTERNAL MAGNETIC FIELD

YAG is a nonmagnetic garnet crystal and YIG is a ferrimagnetic garnet crystal. The sound velocity and the anenuation of the ferrimagnetic garnet and nonmagnetic garnet were studied at high pressures with or without an external magnetic field. The sound velocity was measured by "Pulse Echo Overlap" technique with Matec System Model 6600. The attenuation was measured by comparison of the amplitudes of echoes.We found that both nonmagnetic garnet and ferrimagnetic garnet have some similar ultrasonic behaviou under pressures without magnetic field. We attribute it to their same garnet crystal structure.We also found that there exists magnonspin-phonon interaction in YIG but magnonspin-phonon interaction in YAG, even at high pressures.