巨磁电阻材料La_(0.85)MnO_3的低频内耗和电磁性能  

Low frequency internal friction and electromagnetic properties of colossal magnetoresistance material La_(0.85)MnO_3

作　　者：尹文红[1] 李合琴[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2003年第2期200-202,共3页Journal of Hefei University of Technology：Natural Science

基　　金：安徽省自然科学基金资助项目(03044703)

摘　　要：用低频扭摆法在多功能内耗仪上测量了自掺杂巨磁电阻材料La0.85MnO3的温度内耗谱。结果表明内耗峰位不随频率的变化而变化,但峰高和频率成反比且对应的内耗峰处模量有明显变化,这说明对应的内耗峰处的变化是由某种相变引起的。内耗、电阻及磁化率曲线的对应关系,说明该材料出现了顺磁-铁磁转变和半导体-金属转变,所伴随的结构变化导致了内耗峰的出现。The internal friction and elastic modulus of the colossal magnetoresistance material La0.85MnO3 were measured on the multifunctional internal friction apparatus using the low frequency torsion pendulum. The inverse proportionality of the peak value to the measurement frequency and the invariance of the peak position with the changing frequencies are typical features of phase transition. The corresponding elastic modulus with a local minimum at internal friction peaks also characterizes the nature of phase transition. The relationship between the peak of internal friction and the peak of electric resistance versus temperature is studied based on the analysis of the colossal magnetoresistance effect and the susceptibility. The internal friction corresponding to the resistance peak and Curie temperature can be ascribed to a transition from paramagnetic insulator(PMI) to ferromagnetic metal(FMM).

关 键 词：巨磁电阻材料 La0.85MnO3 电磁性能 低频内耗 磁化率 巨磁电阻效应 居里温度 相变 温度内耗谱 

分 类 号：TM271[一般工业技术—材料科学与工程]