La0.7Ca0.3Mn1-xCuxO3的电输运特性

通过固相反应法制备不同掺杂浓度的La_0.7Ca_0.3Mn_1-xCu_xO₃（x=0~0.15）样品, 在77~300 K温度范围内测量了铜掺杂后样品电阻随温度的变化关系. 结果表明, 在未引入铜杂质时, 低温铁磁相的电阻率满足T^2.5关系, 顺磁相符合小极化子近邻跳跃模型; 在低掺杂下, 铁磁区可用T^4.5关系解释; 随着掺杂浓度的增加, 在铁磁区和顺磁区, 任何单一模型均与实验不相符, 表明高掺杂样品的电输运性质存在未知模型. 

Electric Transport Properties of La0.7Ca0.3Mn1-xCuxO3

La_0.7Ca_0.3Mn_1-xCu_xO₃（ bulk samples with different Cu contents (x=0~0.15) were prepared by solid reaction method. Temperature dependence of Cu doped samples was studied in a range of 77~300 K. The result indicates that the resistivity of the sample without Cu doped follows the T^2.5 model in ferromagnetic phase at low temperatures, while in paramagnetic phase it obeys the small polaron hopping model. Low doped sample match the T^4.5 model at low temperatures in ferromagnetic phase. With the doping content increasing, no single model satisfies our experiment in both ferromagnetic phase and paramagnetic phase. This indicates much more complicated electric transport mechanism of high doped samples.