Alternating-Current Transport Properties of the Interface between Nd_0.7Sr_0.3MnO₃ Ceramic and a Ag Electrode

Electrical transport properties of the interface between a Nd_0.7Sr_0.3MnO₃ ceramic and a Ag electrode are investigated using the ac impedance over a wide temperature and frequency ranges. The ac impedance measurements give the compressed semicircle arcs at different temperatures, which are used for the analysis of different contributions to electrical transport based on an electrical equivalent circuit. A significant interface-dependent electroresistance effect of 530% is clearly developed around the metal-insulator transition temperature 130 K, which is confirmed as the interface-layer dependent Curie temperature by the plot of interfacial conductance with frequency at different temperatures.