Title of article :
Electro-magnetic transport behavior of La0.7Ca0.3MnO3/SnO2 composites
Author/Authors :
Xiong، نويسنده , , C.S. and Huang، نويسنده , , Q.P. and Xiong، نويسنده , , Y.H. and Ren، نويسنده , , Z.M. and Wei، نويسنده , , L.G. and Zhu، نويسنده , , Y.D. and Li، نويسنده , , X.S. and Sun، نويسنده , , C.L.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Pages :
7
From page :
2048
To page :
2054
Abstract :
The composites of (1 − x)La0.7Ca0.3MnO3 (LCMO) + xSnO2 (x = 0.01, 0.05, 0.10, 0.30, 0.50, 0.60, 0.65 and 0.70) were synthesized by conventional solid-state reaction method. The results of X-ray diffraction (XRD) and scanning electronic microscopy (SEM) indicate that SnO2 and LCMO coexist in the composites and SnO2 mainly segregates at the grain boundaries of LCMO, which are in accordance with the results of the magnetic measurements. The detailed electrical characterizations for all the samples showed that a new metal–insulator (M–I) transition temperature (TP2) appeared at a lower temperature compared with the intrinsic metal–insulator (M–I) transition temperature (TP1) when x < 0.50 (TP1 > TP2). When x > 0.50, TP1 disappeared, leaving only TP2. The resistivity percolation threshold of the composites occurred at x = 0.60. Corresponding to the two M–I transition peaks, the curves of magnetoresistance against temperature also showed two peaks for all composites. These phenomena can be explained by the segregation of a new phase related to SnO2 at the grain boundaries or surfaces of the LCMO grains.
Keywords :
A. Electronic materials , D. Dielectric properties , D. Magnetic properties , A. Ceramics
Journal title :
Materials Research Bulletin
Serial Year :
2008
Journal title :
Materials Research Bulletin
Record number :
2106398
Link To Document :
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