【摘要】 采用溶胶 凝胶法并经不同温度烧结而制备了名义组分为La2 /3Ca1/3MnO3和La2 /3Ca1/3Mn1-xCuxO3(x =4 % )的系列样品 ,对它们进行了阻温关系测量 .从试验结果观察到 :在La2 /3Ca1/3MnO3样品中 ,降温和升温测量的阻温曲线几乎完全重合 ,没有观察到明显的热弛豫现象 .而在不同温度烧结的La \- 2 /3Ca1/3Mn1-xCuxO3(x =4 % )样品中 ,阻温关系有明显的热弛豫现象 .同时试验还观察到该热弛豫现象随样品烧结温度 (颗粒尺寸 )的增加逐渐消失更多还原

【Abstract】 The La-{2/3}Ca-{1/3}MnO-3 and La-{2/3}Ca-{1/3}Mn-{1-x}Cu-xO-3 (x=4%) samples are prepared with sol-gel method as sintering treatment at difference temperature. We perform measurements of resistivity versus temperature dependence in both cooling and warming modes. For the x=0 sample, resistivity versus temperature dependence in both cooling and warming modes are unanimous. Unusual thermal hysteresis is observed in the Cu doped samples. The thermal hysteresis disappear gradually with increasing of the sintering temperature(hence the grain size).更多还原