Magnetoresistance of La0.7Sr0.3MnO3 thin films obtained by magnetron sputtering on different substrates

Thin films of La0.7Sr0.3MnO3 (LSMO) have been deposited by magnetron sputte ring on LaAlO3 (LAO), SrTiO3 (STO), MgO, Si/Si3N4, Si/MgO and Si/YSZ substr ates. Buffer layers of YSZ, MgO and Si3N4 have been obtained by magnetron s puttering or chemical vapour deposition techniques. The influence of deposi tion parameters, substrate temperature as well as lattice mismatch between the substrate and manganite layer on magnetoresistance of obtained films ha ve been investigated. The magnetoresistance MR = [R(H) - R(0)]/R(0), where R(H) and R(0) is the film resistance in and without magnetic field, has bee n measured in in-plane and out-of-plane direction of applied magnetic field H. The polycrystalline films, especially on Si/Si3N4 substrates, exhibited significant low-field MR. The LSMO films obtained at elevated temperature on LAO or STO substrates possessed low-resistivity values and metallic resi stivity up to T > 300 K, implying possible applications in tunneling struct ures. (C) 2000 Elsevier Science Ltd. All rights reserved.