电子顺磁共振研究巨磁电阻锰氧化物La_(0.67)Ca_(0.33)MnO_3的顺磁到铁磁的相变

Electron paramagnetic resonance studies of magnetic transition in La_(0.67)Ca_(0.33)MnO_3 with CMR

采用高温固态反应法制备了具有钙钛矿结构的多晶氧化物La0 67Ca0 33MnO3,利用X射线衍射、电子顺磁共振等实验技术研究其结构和顺磁到铁磁的磁性相转变.电子顺磁共振实验可以观测到样品在磁有序转变温度(Tc)附近的动态磁性相转变,并且与磁化强度的实验结果一致.对Tc附近的磁性相转变进行了分析.

The colossal magnetoresistance manganite(CMR) La_(067)Ca_(033)MnO_3 was prepared by conventional solid state reaction method. The dynamic magnetic transition was investigated by EPR experiment near the (Curie) temperature T_c, and the results are in agreement with the magnetization experiments. The EPR investigation indicated that the compound was in the paramagnetic phase above 272 K, whereas it was in the ferromagnetic state below 260 K.