AC properties of Pr0.7Ca0.3MnO3 ceramics

作者：Shi Da Wei; Wu Mei Ling; Yang Chang Ping^*; Ren Chun Ling; Xiao Hai Bo; Wang Kai Ying

来源：Acta Physica Sinica, 2013, 62(2): 026201.

DOI：10.7498/aps.62.026201

• perovskite manganite oxide
• colossal magnetoresistance (CMR)
• Schottky barrier
• space charge region

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.

• 出版日期2013
• 单位湖北大学