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采用溶胶-凝胶法制备了系列多晶CMR材料La2/3(Ca0.60Ba0.40)1/3Mn1-xVxO3(x=0%、1%、5%、7%、10%、15%、20%).在零场下、77~350K温度范围内测量了其电阻率随温度的变化关系,测量了该温度范围内0.1 T磁场下磁化强度随温度的变化关系.采用小极化子绝热跃迁模型ρ=αTexp(E/kT)对样品的电导特性进行拟合研究.结果发现,高温区电阻率随温度的变化很好地满足小极化子绝热跃迁模型;同时,采用单磁子散射模型对样品低温区的电输运曲线进行拟合,结果发现所有样品低温区的ρ~T关系同样都很好地满足单磁子散射公式ρ=ρ0+AT2.由拟合结果分析了样品高温区的输运行为主要来源于小极化子的影响,而低温区电导特性主要来源于单磁子散射.
A series of polycrystalline CMR materials La2 / 3 (Ca0.60Ba0.40) 1 / 3Mn1-xVxO3 (x = 0%, 1%, 5%, 7%, 10%, 15%, 20 %) Under the zero field, the temperature dependence of the resistivity was measured in the temperature range of 77 ~ 350K, and the relationship between the magnetization and the temperature was measured under 0.1 T magnetic field in this temperature range.With the small polaron adiabatic transition The model ρ = αTexp (E / kT) was used to fit the conductivity characteristics of the samples. The results show that the resistivity transitions of the high temperature region satisfy the small polaron adiabatic transition model well with the change of temperature. Fitting the electric transport curve in the low temperature region of the sample, the results show that the ρ ~ T relationship of the low temperature region of all the samples also satisfies the single-magnet scattering formula ρ = ρ0 + AT2 well.The analysis of the high temperature region The transport behavior mainly comes from the effect of small polaron, while the conductivity of low temperature mainly comes from single-magnet scattering.