Electron spin resonance of valence fluctuating compounds.

1.利用脉冲磁铁在大阪大学极端材料研究中心建立了强磁场ESR高场ESR光谱仪系统，研究了价态起伏化合物的带隙消失现象。本实验研究的是五水合硫酸铜CuSO_45H_2O。发现了与温度相关的交换作用J_&lt；AB&gt；[J.Phys.Soc.Jpn.57(1988)4366]现在我们不仅用ESR系统研究价波动化合物，而且还研究重费米子材料。2.GdBe单晶的ESR研究GdBe单晶的ESR研究与Rb_6型价波动化合物的比较。观察到了Gd^&lt；3+和Gt；的顺磁共振和反铁磁共振。3.用ESR研究了氧化钕铜氧化物Nd2CuO4的电子自旋共振，在30K以下观察到了较宽的共振。这种共振是由ND自旋引起的，没有发现来自铜自旋的共振。G值是各向同性的，在10K以上的值为0.85，与自由离子的0.73相差不大。然而，在约5K以下，g值随温度的降低而迅速下降，且与角度有很大的关系。提出了Nd-Cu相互作用对ND自旋的影响。作者声明：[J.Phys.SoC。日本。价波动化合物的ESR研究。(1987年前)1)SMB_6中Eu和Gd离子的电子自旋共振。访问数/每百万人：Reach for[J.52(1985)271-274。]2)SMB_6中Eu~(2+)~(2+)的高次谐波电子自旋共振。访问数/每百万人：Reach for[J.日本。55(1986)43-46.]3)SmB_6中无序Sm离子的电子自旋共振.作者声明：[J.Phys.SoC。日本。55(1986)3737-3740。]

1. High-magnetic field ESR High-field ESR spectrometer system using pulse magnet in the Research Center for Extreme Materials, Osaka, University was made to investigate the disappearance of band gap of valence fluctuating compounds. The test investigation is the study of Copper sulfate pentahydrate CuSO_45H_2O. The temperature dependent exchange interaction J_<AB> is found. [J.Phys.Soc.Jpn.57(1988)4366] Now we are using the ESR system to study not only valence fluctuating compounds but also heavy fermion materials.2.ESR study of GdB_6 The ESR study of GdBe single crystal was done to compare with the RB_6 type valence fluctuation compounds. The paramagnetic resonance of Gd^<3+> and the antiferromagnetic resonance was observed.3.ESR Study of Nd_2CuO_4 Electron spin resonance of neodymium copper oxide Nd_2CuO_4 is investigated and broad resonance is observed below 30K. The resonance is attributed to the Nd spin and no resonance from Cu spin is found. The g-value is isotropic with the value of 0.85 above 10K which is not so far from Nd<^<3+> free ion value of 0.73. Below about 5K, however, the g-value decreases rapidly with decreasing temperature with a large angular dependence. Effect of the Nd-Cu interactions on the Nd spin is suggest. [J. Phys. Soc. Jpn. to be published.]4.ESR study of valence fluctuating compounds. ( before 1987) 1)Electron spin resonance of Eu and Gd ions in SmB_6. [J.Magn.Magn.Mater. 52(1985)271-274.] 2)Higher harmonic electron spin resonance of Eu^<2+> in SmB_6. [J.Phys.Soc. Jpn. 55(1986)43-46.] 3)Electron spin resonance of disordered Sm ions in SmB_6. [J.Phys. Soc. Jpn. 55(1986)3737-3740.]