Liquid-phase sintering method was used to prepare BaTiO3 powders and the structure and electrical properties of (1-x)BaTiO3+(x)La2/3Sr1/3MnO3 (LSMO) composites were investigated. The results of X-ray diffraction showed that the prepared BaTiO3 powders were pure and fine, indicating that sintering temperature was effectively lowered when the NaCl sintering aid was added. X-ray diffraction patterns of \linebreak\noindent (1-x)BaTiO3+(x)La2/3Sr1/3MnO3 (LSMO) composites showed that LSMO and BaTiO3 phases were coexistent and no other phases were detected. The impedance spectra showed that the resistance of grain boundaries for LSMO-doped samples was suppressed. The resistivity-temperature measurements showed that room-temperature resistivity of the composites was lowered from insulator for pure BaTiO3 ceramic to 103Ω•m for the x=0.3 sample. The sample of x≤0.2 showed the positive temperature coefficient (PTC) effect whereas the x=0.3 sample exhibited PTC effect at temperatures below 68 ℃ and then negative temperature coefficient (NTC) effect at temperatures above 68 ℃. The related mechanism has been elucidated.
ZHOU Zheng-Wei
. Structure and electrical properties of (1-x)BaTiO3+(x)La2/3-Sr1/3MnO3 composites[J]. Acta Metallurgica Sinica (English Letters), 2011
, 24(4)
: 315
-320
.
DOI: 10.11890/1006-7191-114-315
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