Current induced metastable states and abnormal electroresistance effect in epitaxial thin films of La0.8Ca0.2MnO3

By applying an electric current to La0.8Ca0.2MnO3 films at 20 K, a high-resistive state is excited near the Curie point. Such a current induced metastable state turns out to be extremely sensitive to weak measuring currents. When the measuring current changes from 1 to 20 μA, the peak resistance near the metal–insulator transition temperature is reduced from 366 to 111 k Ω , showing a remarkably enhanced electroresistance effect ( E R = [ R ( 0 ) − R ( I ) ] / R ( 0 ) = 70 % ) . Also, in contrast to the previous reports, the metal–insulator transition shifts to a higher temperature. Our experiments show that the high-resistive state is metastable and cannot be removed by reversing the current direction. These behaviors yield a possibility to modulate the metal–insulator phase transition by using electric currents.