作　　者： ; ; ;

机构地区： 福建农林大学机电工程学院

出　　处： 《低温物理学报》 2008年第3期217-221,共5页

摘　　要： 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 polycrystal bulk samples of La2/3 （ Ca0. 60 Ba0.40 ）1/3 M n1-x, VxO3 （x = 0%, 1% ,5 % ,7 %, 10%, 15%, 20% ） have been prepared by Sol-Gel process. The temperature dependences of resistance in zero field of all the samples were measured from 77 K up to 350 K, the temperature dependences of magnetization under the field B = 0. 1 T of them in this temperature range were measured meanwhile. Adiabatic small polaron hopping model ρ = αTexp （E/kT） was used to study the electrical conductivity properties in high temperature range of all the samples. From the fitting results we found that the ρ - T curves in this temperature range can be well fitted by the model. Then single magnon scattering model ρ =P0 ＋AT^2 was used to fit the ρ - T curves in low temperature ferromagnetic phase, which shows that they fit well. According to the fitting results, the orient of the electrical transport properties for the samples were analyzed

关 键 词： 小极化子绝热跃迁 单磁子散射模型 高温区 低温区

领　　域： [理学] [理学] [电子电信]