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Abstract
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In this paper, the relationship between anisotropic magnetoresistance (AMR) and phase separation in La0.4Pr0.3Ca0.3MnO3 (LPCMO)/NGO films has been investigated. The films were grown on orthorhombic NGO (001) single crystal substrates by the pulsed laser deposition (PLD) method. The as-grown films were ex-situ annealed at 780 °C for 30 min in 400 mTorr oxygen pressures to clarify the effects of annealing on magnetoresistance (MR) and AMR. The X-ray diffraction (XRD) pattern confirmed that the substrate distance from the target is a key parameter for strong preferred crystallographic orientation growth. The temperature-dependent resistivity of the as-grown films revealed the coexistence of ferromagnetic and antiferromagnetic phases and the frozen glassy state at low temperatures. In the film with significant phase coexistence, the considerably large AMR and MR values of about 140% and 100% are achieved under the 5 kOe magnetic field. By tuning the target-substrate distance, different crystalline orientations of LPCMO can be obtained, and as a result, the metal-insulator transition (MIT) temperature, MR, and AMR can be modified.
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