J. Appl. Phys. 101, 123906 (2007)

Abstract

The temperature, current, and magnetic field dependences of the transport properties at the interface between La_0.8Ca_0.2MnO₃ and Nb(0.1%):SrTiO₃ were studied. The striking feature in the present transport data is the appearance of a charging effect that typically occurs in RC circuits. It can be well modeled by a simple RC equivalent circuit. The results show that the interface of the present junctions has a very large capacitance with a value of the areal capacitance of 60 nF/mm² leading to a very large time constant of the order of 100 s at 100 K. Both the interfacial resistance and the time constant significantly decrease with increasing temperature, current, and magnetic field, whereas the interfacial capacitance remains essentially unchanged. This phenomenon opens up the possibility for the development of a different type of current, magnetic field, and temperature sensitive capacitor.