溶胶凝胶法制备La_(0.7)Ca_(0.3)MnO_3薄膜庞磁电阻效应和电流诱导电阻特性

Sol-gel epitaxial growth of La_(0.7)Ca_(0.3)MnO_(3) with colossal magnetoresistance and current-induced resistivity properties

采用溶胶凝胶法成功制备了La0.7 Ca0.3MnO3块材和单晶薄膜,研究了薄膜的电阻随温度的变化特性,以及在不同的恒定电流下,薄膜的电阻的变化特性,实验发现在同一温度下,电阻随着电流的增大而变小,在同一稳恒电流下,在T>Tc 时,电阻随着温度的升高而变小;并且出现了双极值现象。这些输运特性可以采用双交换作用和晶格畸变产生的小极化子的机制来解释。

La0.7Ca0.3MnO3 thin film with colossal magnetoresistance was fabricated by sol-gel method. Temperature dependence of the resistivity for La0.7Ca0.3MnO3 thin film and the resistivity change induced by current and magnetic fields have been studied. Increasing currents or magnetic fields, the resistivity for thin film decreases. Experimental results show that the insulator-metal transition. It was the interaction between double exchange and polarons that played an important role in CMR thin films.