ESR Study of Heavy Fermion State

1)研究了Nd_2CuO_4单晶的高磁场磁化，发现了自旋翻转和未识别的相变。这些跃迁归因于Nd自旋系统中的跃迁，而不是Cu和Nd自旋之间的相互作用。这对跃迁来说是不可忽略的。ESR测量支持当前模型。2) Nd_2CuO_4中观察到的电子自旋共振异常归因于Nd- cu自旋网络中Nd自旋的反铁磁共振（AFMR）。这种异常来自于nd位上铜自旋引起的交错场。铜自旋形成一个紧密的反铁磁自旋网络，在nd共振过程中几乎处于静止状态。交错场在Nd自旋上作为一个额外的各向异性场。AFMR中各磁参量与高磁场研究结果一致。

1)High field magnetization of Nd_2CuO_4 single crystal Is lnvestigated and the spin-flop and unidentified phase transitions are found. These transitions are attributed to those In the Nd spin system but the Interaction between Cu and Nd spins. ts not negligible to the transitions. The ESR measurement supports the present model.2)Anomalous electron spin resonance observed in Nd_2CuO_4 is attributed to antiferromagnetic resonance(AFMR)of Nd spins in the Nd-Cu spin network. The anomaly comes from the staggered field due to Cu spins on the Nd-site. The Cu spins form a tight antiferromagnetic spin network and are almost at rest during the Nd-resonance. The staggered field acts as an additional anisotropy field on the Nd spin. Various magnetic parameters in AFMR are in accord with those determined by the high field magnetization study.