Crossover from charge order to strain glass in phase separated manganite thin films: Impact of thermal cycling and substrate induced strain

The magnetic and electrical transport properties of single crystalline La1−x−yPryCaxMnO3 (x≈0.42, y≈0.40) thin films (~140 nm) deposited on (1 1 0) oriented LaAlO3 and SrTiO3 substrates have been investigated. The magnetotransport properties of these films exhibit substrate dependent phase separation and a crossover from the high temperature antiferromagnetic-charge ordered insulator (AFM-COI) phase (T>TC) to strain glass (T<Tg). At intermediate temperatures (Tg≤T≤TC) dynamical liquid having prominent thermal-magneto-resistive hysteresis dominates in the cooling cycle while in the warming cycle it is preceded by ferromagnetic metal (FMM) phase. Magnetic fields required to drive AFM-COI to FMM phase transition are higher than required for the strain glass to FMM transformation. The magneto-electric transitions and temperature span of the distinct magnetic regimes are sensitive to the thermal cycling and substrate induced strain.