【作者】 葛洪良； 程素君； 郭金锁； 蒋丽珍； 王新燕； 崔玉建；

【Author】 Ge Hongliang, Cheng Sujun, Guo Jinsuo, Jiang Ldzhen, Wang Xinyan, Cui Yujian(Department of Physics , China Institute of Metrology, Hangzhou 310018, China;Department of Physics, Xinxiang Teachers’ College, Xinxiang 453000, China)

【机构】 中国计量学院应用物理系； 新乡高等师范专科学校物理系；

【摘要】 研究了La0.67Ca0.33Mn1-xFexO3和(La1-xCex)0.67Ca0.33MnO3的结构以及输运特性、磁化强度随温度的变化。结果表明,随掺杂量x的增加,两种体系的电阻率急剧增加,绝缘-金属转变温度T_MI和顺磁-铁磁(PM-FM)转变温度Tc向低温方向移动。当T<Tc时,La0.67Ca0.33Mn1-xFexO3(x=0.00～0.08)呈现铁磁性;而(La1-xCex)0.67Ca0.33MnO3(x=0.00-0.70)出现了铁磁-反铁磁(FM-AFM)转变,FM-AFM转变温度T_N随掺杂量的增加向高温方向移动。Fe离子掺杂容易形成Fe3+-O2-Mn4+通道,阻塞了Mn3+-O2--Mn4+双交换作用通道,同时晶格磁性局域激化与载流子运动存在一定的关联;Ce离子掺杂不仅会影响体系的结构,而且其价态的涨落会引起体系中空穴的出现,进而影响体系的输运性质和磁结构。更多还原

【Abstract】 The structure, transport and magnetic properties of La0.67Ca0.33 Mn1-xFexO3(x=0-0.3) and (La1-xCex)2/3Ca1/3MnO3(x=0.1-0.9) changing with temperature were studied. It is found that with increasing doping content x the resistivity increases rapidly and the insulator-metal transition temperature TMI and paramagnetic-ferromagnetic transition temperature Tc moves to lower temperature. When T<Tc, La0.67Ca0.33Mn1-xFexO3(x=0.00-0.08) exhibits ferromagnetic properties but (La1-xCex)2/3Ca1/3MnO3 (x=0.00-0.70) presents paramagnetic-ferromag- netic (PM-FM ) transition, and the temperature T_N moves to high temperature with increasing doping content, Fe ion doping, which makes it easy to form Fe3+ - O2- -Mn4+ channel, terminates the double exchange Mn3+ - O2- -Mn4+ channel, and at same time, the movement of current carrier are associated with the local polarization of lattice magnetic properties; Ce ion doping not only changes the structure of the system, but also effects the transport properties and magnetic structure, which is due to the apparance of the hole caused by the fluctuation of valence state.更多还原