Investigations on electroresistance effect in epitaxial manganite films using field effect configurations

摘要

The influence of static electric field on the transport properties in La_(0.7)A_(0.3)MnO_3 (A=Ca,Ba) epitaxial thin films was investigated by using field effect configurations (FEC). A single layer manganite film was deposited on LaAlO_3 (LAO) substrate by pulsed laser deposition technique, and then a simple FEC was formed on it using the lithography technique, in which the manganite film was used as a channel, and the LAO substrate as a gate. Surprising results were achieved by employing such a FEC. The transport resistance increases with a positive gate voltage but decreases with a negative bias, which means the electroresistance (ER) effect changes sign with the field direction. The observed reduction of resistivity for the La_(0.7)Ca_(0.3)MnO_3 and La_(0.7)Ba_(0.3)MnO_3 channels reaches ～32% and ～34% upon a bias of -80 and -300 V, respectively. The films could completely return to their pristine state after the bias was removed and the ER effect could be fully reproduced.