Metastable magnetic state and magnetotransport in disordered manganite thin films

摘要

We report on the magnetic, electrical, and magnetotransport properties of La_(0.7)Ca_(0.3)Mn_(1-x)Al_xO_3 (X = 0, 0.05, 0.15) thin films grown on LaAlO_3 (001) substrate. It is observed that the low temperature ferromagnetic phase of La_(0.7)Ca_(0.3)Mn_(1-x)Al_xO_3 transforms into metastable magnetic state in 15 at. ％ Al doped sample, which has been characterized using long-time relaxation measurement as well as different temperature sweep rates (during cooling and heating) of magnetization measurements. Our results clearly show that the magnetic transition in this film is connected with the kinetics of first order phase transition. The metastable magnetic phase also shows increased magnetoresistance.