Open AccessAC properties of Pr0.7Ca0.3MnO3 ceramics
Author(s) -
石大为,
吴美玲,
杨昌平,
任春林,
肖海波,
王开鹰
Publication year - 2013
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.62.026201
Subject(s) - materials science , ceramic , grain boundary , curie temperature , condensed matter physics , magnetoresistance , magnetic field , colossal magnetoresistance , field (mathematics) , magnetometer , magnetization , nuclear magnetic resonance , microstructure , composite material , physics , ferromagnetism , mathematics , quantum mechanics , pure mathematics
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.