论文部分内容阅读
研究制备了 L a0 .6 7Ba0 .3 3Mn1 - x Fex O3(x=0 ,0 .0 5 ,0 .1)材料。结果表明 :铁替换锰降低了材料的饱和磁化强度及居里温度 ,主要是因为 Fe离子不参加双交换作用 ,同时 Mn3+ - O2 - - Mn4+ 的作用对随铁离子替代 Mn3+ 而数量减少 ,材料的铁磁作用随之减弱。铁替换锰降低了金属 -半导体转换峰温度 ,相应提高了材料的零场电阻值。值得注意的是铁掺杂提高了大磁阻材料 L a0 .6 7Ba0 .3 3Mn1 - x Fex O3的低温性能 ,5 K下磁阻比 [R(6 T) - R(0 ) ]/ R(0 )从 x=0时的- 40 %增加到 x=0 .1时的 - 6 0 %。本文同时利用迪尼模型对材料大磁阻效应进行了计算分析 ,发现理论计算曲线可以较好的反映实验上出现的金属 -半导体转换峰现象 ,同时负的大磁阻效应现象也可从理论计算上得到证实。
L a0 .6 7Ba0 .3 3Mn1 - xFexO3 (x = 0,0.5,0.1) materials were prepared. The results show that the substitution of manganese with iron reduces the saturation magnetization and the Curie temperature of the material, mainly because Fe ions do not participate in double exchange and the effect of Mn3 + - O2 - - Mn4 + decreases with the substitution of Mn3 + with iron. The iron Magnetic effect will be weakened. The replacement of manganese by iron reduces the temperature of the metal-semiconductor transition peak and correspondingly increases the zero-field resistance of the material. It is noteworthy that the iron doping improves the low temperature performance of the large magnetoresistive material L a0 .6 7Ba0 .3 3Mn1 - x Fex O3. The magnetoresistance ratio [R (6 T) - R (0)] / R 0) increases from -40% at x = 0 to -6 0% at x = 0 .1. In this paper, the Dini model is also used to calculate and analyze the large magnetoresistance effect of the material, and the theoretical calculation curve can better reflect the phenomenon of metal-semiconductor transition peak appearing experimentally. Meanwhile, the phenomenon of the negative giant magnetoresistive effect can also be calculated theoretically Confirmed on.