摘要
用溶胶-凝胶法制备了系列掺杂（La0.8Ln0.2）2/3Ca1/3MnO3（Ln=La，Ce，Pr，Nd，Sm，Eu）纳米级晶体。对比在La被其它镧系元素部分替代后，引起的A位离子平均半径的改变和磁矩变化对电输运及磁阻性能的影响，实验分析表明，各个样品在同样大小磁场下的磁电阻存在较大的差别，样品的磁电阻随原子序数的增加而明显变大，由镧系收缩引起晶格畸变所产生的本征磁电阻占主导地位，随着外加磁场的增加，不同掺杂样品间的峰值电阻差异被弱化；各掺杂样品间的转变温度差与掺杂离子半径差和磁矩差密切相关，且离子半径的差异对转变温度的改变贡献更大。
Sol-gel method was employed to prepare Ln-doped （La0.8Ln0.2）2/3Ca1/3MnO3（Ln=La,Ce,Pr,Nd,Sm,Eu） nanoscale crystals. The influences of replacement of lanthanide elements on magnetoresistance and electrical transport performances resulted from the change of average radius of A-site ions and magnetic moment. Experimental results show that the magnetic resistances between different samples under same magnetic field have large differences and the magnetic resistance would increase obviously with increasing atomic number. The intrinsic magnetic resistance resulted from lattice distortion caused by the lanthanides contraction are dominant. The difference of peak resistance between different doped samples was weakened with the increase of magnetic field. The difference of transition temperature between different doped samples had very close relationship with the difference of doped ion radius and magnetic moment, and the difference of doping ion radius is dominant.
关键词
溶胶-凝胶法
纳米晶体
等量掺杂
磁电阻
sol-gel technique
nanocrystalline
equal doping
magnetic resistance
