Thickness dependence of electroresistance in La0.67Ca0.33MnO3 epitaxial films

The electroresistance (ER) of La0.67Ca0.33MnO3 (LCMO) epitaxial thin films with different thicknesses was studied. For the 110 nm thick LCMO film, its ER shows a maximum at Tp, where the resistance shows a peak, and decreases to zero at lower temperatures. While for the 30 nm thick LCMO film, its ER is remarkable in a wide temperature range. Another interesting observation in this work is that the electric current can tune the magnetoresistance of the ultrathin LCMO thin film. The results were discussed by considering the coexistence of ferromagnetic metallic phase with the charge ordered phase, and the variation of the phase separation with film thickness and electric current. This work also demonstrates that electric current can tune the magnetoresistance of the manganites, which is helpful for their applications.