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研究了La0.67Sr0.33Mn1-xCrxO3(0.00≤x≤0.30)体系的M-T曲线、ρ-T曲线和MR-T曲线。实验结果表明:Cr对Mn位的替代对居里温度TC影响不明显,但是随着Cr含量的增加,电阻率和磁电阻出现双峰行为,CMR效应的温区被极大地拓宽了。体系的特殊输运行为和异常CMR效应可能是Mn3+-O-Mn4+和Mn3+-O-Cr3+两种通道共存和竞争的结果。
The M-T curve, ρ-T curve and MR-T curve of La0.67Sr0.33Mn1-xCrxO3 (0.00≤x≤0.30) were studied. The experimental results show that the substitution of Cr for Mn has no obvious effect on the Curie temperature TC. However, with the increase of Cr content, the bimodal behavior of resistivity and magnetoresistance appears. The temperature range of CMR effect is greatly broadened. The special transport and abnormal CMR effects of the system may be the result of the coexistence and competition between the two channels of Mn3 + -O-Mn4 + and Mn3 + -O-Cr3 +.