Origin of an enhanced colossal magnetoresistance effect in epitaxial Nd0.52Sr0.48MnO3 thin films

Анотація

Nd_0.52Sr_0.48MnO₃ films with the different thickness have been prepared by dc magnetron sputtering on LaAlO₃ (001) single-crystalline substrates. A decrease of the film thickness leads to a significant suppression of the ferromagnetic (FM) ordering and the Curie point becomes below the antiferromagnetic (AFM) transition temperature. As this take place, a huge rise of the magnetoresistance ratio from 400 to 60 000% at an applied magnetic field of 5 T is observed. We consider that this new kind of the enhanced colossal magnetoresistance effect is originated from the FM/AFM competition and the collapse of the charge-ordered state at high magnetic field rather than through the regular double-exchange mechanism.