La_(0.95)K_(0.05)MnO_3的低频内耗研究  

LOW FREQUENCY INTERNAL FRICTION STUDY OF PHASE TRANSITION IN La_(0.95)K_(0.05)MnO_3 BULK MATERIALS

作　　者：王广涛[1] 张敏平[1] 万陵德[1] 陈健[1] 

机构地区：[1]河南师范大学物理系信息与工程学院,新乡453002

出　　处：《低温物理学报》2004年第4期280-287,共8页Low Temperature Physical Letters

摘　　要：本文研究了样品La0 .95 K0 .0 5 MnO3 的内耗、直流电阻、交流磁化率 .发现在 2 0～ 2 75K的温度范围内 ,在 0 .3T的磁场下有明显的磁阻 (MR)效应 ,温度为 2 59K时MR效应达到极大值 2 6 % .在直流电阻测量中发现 2 6 7K时出现很尖锐的电阻峰 ;在 2 2 0K附近出现“肩峰” .内耗温度曲线在 2 1 0K～ 2 50K的温度范围有一个很宽的内耗峰 ;在 2 6 8K有一个很明显的内耗蜂同时伴随着模量软化 ,并且由Kissinger关系求出顺磁 铁磁转变的表观激活能Eap=0 .53eV(请说明通过什么公式求出什么东西的活化能 )La-{0.95}K-{0.05}MnO-3 has been studied by the internal friction, electrical resistance and AC magnetic susceptibility. Large magnetoresistance (MR) exists in a wide temperature range (20～275K) in La-{0.95}K-{0.05}MnO-3 specimen at low magnetic field (0.3T). A sharp peak (T=267K) and a shoulder peak (T=220K) are observed in the R-T curve. Accompanied with the local minimum of elastic modulus, the internal friction measurement reveals two peaks at about 268K and 230K. The position of the peaks in Q+{-1} do not shift with frequency, but their height of the peaks in Q+{-1} decrease with frequency increasing, which are general characters of the low frequency internal friction associated with the phase transition. The apparent activation energy of the phase transition E-{ap} was obtained as 0.53eV. From above experiments we draw the conclusion that there exists the phase separation in the sample.

关 键 词：直流电阻 低频内耗 磁阻 交流磁化率 测量 磁场 极大值 激活能 内耗峰 温度范围 

分 类 号：TB39[一般工业技术—材料科学与工程]