-
采用固相烧结方法制备了Pr1-xCaxMnO3(x=0.3) 钙态矿结构锰氧化物陶瓷样品, 对其在磁场和电场下的直、交流输运性质做了系统研究. 通过测量加磁场和零场下的I-V曲线, 得到其居里温度为150 K, 与VSM 测试结果一致. 通过测量加磁场与零场下交流的阻抗频谱, 发现加磁场后样品的晶界电阻明显减小, 而晶粒电阻几乎保持不变, 表明Pr1-xCaxMnO3陶瓷多晶样品的CMR效应源于样品的晶界. 为确定晶界处的势垒高度, 测量了样品在不同频率下的阻抗温谱, 根据Arrhenius定律拟合得出势垒高度为117 meV, 与用直流R-T数据拟合得出的激活能一致.Ceramic Pr1-xCaxMnO3(x=0.3) samples are prepared by solid-state reaction and measured using direct current (DC) and alternating current (AC) methods in different magnetic and electrical fields. A Curie temperature of 150 K is determined by I-V measurements in field for Pr0.7Ca0.3MnO3, which is consistent with that from vibrating sample magnetometer (VSM). The AC measurement shows that the grain boundary resistance reduces with magnetic field increasing, while the grain almost keeps unchanged, and it indicates that the colossal magnetoresistance (CMR) effect in low field mainly comes from the grain boundary for the Pr0.7Ca0.3MnO3 ceramic. The barrier height of grain boundary is 117 meV for the Pr0.7Ca0.3MnO3 ceramic, obtained by fitting the temperature spectrum of impedance, and it is well coincident with that from fitting the R-T data. A trap state model is proposed to explain all the measured data.
-
Keywords:
- perovskite manganite oxide /
- colossal magnetoresistance (CMR) /
- Schottky barrier /
- space charge region
[1] Jin S, Tiefel T H, McCormack M, Fastnacht R A, Ramesh R, Chen L H 1994 Science 264 413
[2] Dagotto E, Hotta T, Moreo A 2001 Phys. Report 344 1
[3] Liu J M, Wang K F 2005 Progress in Physics 25 82 (in Chinese) [刘俊明, 王克锋 2005 物理学进展 25 82]
[4] Dong S, Liu J M 2010 Progress in Physics 30 1 (in Chinese) [董帅, 刘俊明 2010 物理学进展 30 1]
[5] Martin C, Maignan A, Hervieu M, Raveau B 2002 Phys. Rev. B 66 094410
[6] Yang C P, Chen S S, Zhou Z H, Xu L F, Wang H, Hu J F, Morchshakov V, Bärner K 2007 J. Appl. Phys. 101 063909
-
[1] Jin S, Tiefel T H, McCormack M, Fastnacht R A, Ramesh R, Chen L H 1994 Science 264 413
[2] Dagotto E, Hotta T, Moreo A 2001 Phys. Report 344 1
[3] Liu J M, Wang K F 2005 Progress in Physics 25 82 (in Chinese) [刘俊明, 王克锋 2005 物理学进展 25 82]
[4] Dong S, Liu J M 2010 Progress in Physics 30 1 (in Chinese) [董帅, 刘俊明 2010 物理学进展 30 1]
[5] Martin C, Maignan A, Hervieu M, Raveau B 2002 Phys. Rev. B 66 094410
[6] Yang C P, Chen S S, Zhou Z H, Xu L F, Wang H, Hu J F, Morchshakov V, Bärner K 2007 J. Appl. Phys. 101 063909
计量
- 文章访问数: 7291
- PDF下载量: 606
- 被引次数: 0
下载:
