钙钛矿结构锰氧化物Pr_(1-x)Ca_xMnO_3(0.4≤x≤0.5)纳米材料的磁性质研究

The Study of Magnetic Properties of Nanoparticle Manganite Pr_(1-x)Ca_xMnO_3(0.4≤x≤0.5)

采用溶胶凝胶法制备了Pr1-xCaxMnO3(0.4≤x≤0.5)系列纳米样品,对其磁性质进行了研究.所有样品在M-T曲线中250K附近的电荷有序转变和170K附近的顺磁-反铁磁转变都消失,与Dong等人的理论模拟计算相符.所有样品在40K都出现了Reentrant spin glass(RSG)态.随着Ca2+掺杂浓度的增加,Mn3+/Mn4+的比例迅速变小,破坏了Mn-O-Mn导电通道,导致磁化强度M逐渐变小.

The nanoparticle samples of Pr 1 -xCaxMn03 （0.4 ≤x ≤0.5 ）were prepared by sol-gel method. The magnetic properties of these samples were studied. The M-T curves show that the transtition of charge order （CO） at 250K and the transition from paramagnetie to antiferromagnetic at 170 K both are not observed. The experimental results are in agreement with the theoretical computation of Dong et al. The state of Reentrant spin glass （RSG）of these samples is observed at 40K. The ratio of Mn3 ＋/Mn4＋ is sharply reducing with the amount doped of Caz＋ increasing. This is caused by that the conductive channel of Mn-O-Mn is disrupted. It gives rise to that the intensity of magnetization are decreasing.