La_(0.5-x)Nd_xBa_(0.5)CoO_3化合物的磁性和输运特性

Magnetic and Transport Properties of La_(0.5-x)Nd_xBa_(0.5)CoO_3 Compounds

在La0 .5Ba0 .5CoO3 化合物中用Nd对La进行了替代研究 ,结果表明 ,Nd的掺入未改变Co3d电子的巡游性。随Nd含量增大 ,材料的分子磁矩单调下降 ,当Nd含量大于或等于 0 .45时 ,材料中出现了磁性相分离。当x≤ 0 .45时 ,随Nd含量增加 ,材料的居里温度单调下降 ,这是由于稀土离子的尺寸效应。电阻测量表明 ,在所研究的温度范围内 ,在居里点以下 ,材料属热扩散导电。

Substituting effects of Nd for La in La_ 0.5Ba_ 0.5CoO_3 compounds were studied. The results show that substitution of Nd does not change the itinerant properties of the Co3d electrons. The molecular moment of the materials decreases monotonically with increasing of Nd content. When Nd content is greater or equal to 0.45, magnetic phase separation in the materials appears. When x≤0.45, the Curie temperature of the materials decreases monotonically with the increase of Nd content. This is due to the size effect of the rare-earth ions. The electric resistance measurements show that in the studied temperature range, the conduction of the materials below Curie temperature is of thermal diffusion conduction, whereas, higher than Curie temperature the conductive mechanism of the materials is the variable range hopping conduction of polarons.