La-Ca-(Mn,Fe)-O大磁阻材料的低温特性

Low Temperature Behavior of La-Ca(Mn,Fe)-O CMR Materials

研究了低温下La Ca (Mn ,Fe) O的磁性及磁阻特性。发现随着铁离子替代锰离子 ,材料中的铁磁作用减弱 ,反铁磁作用增强。在铁替代锰量为 1/10的样品中 ,在磁化曲线及磁阻变化的关系上 ,发现了“弯曲”现象 ,并给出了物理解释。另外还发现少量的铁离子替代锰离子可提高材料的低温磁阻比值。

The magnetic and magnetoresistance behavior of La Ca (Mn,Fe) O materials was investigated at low temperature. The result shows that with the increasing replacement of Mn by Fe, the ferromagnetic interaction of samples decreases but the antiferromagnetic interaction increases. The new phenomenon of the “bending” in the magnetization process and the field dependence of magnetoresistance were found in the sample with Mn∶Fe=9∶1 and the physical mechanism was studied. Small replacement of Mn by Fe increases the low temperature CMR value in La Ca (Mn, Fe) O materials.