Low field magnetotransport properties of „La0.7Sr0.3MnO3...0.5: „ZnO...0.5 nanocomposite films

La0.7Sr0.3MnO3 0.5 : ZnO 0.5 nanocomposite thin films were deposited on c-cut sapphire substrates via pulsed laser deposition. The as-grown films were composed of fine grains of 20–50 nm size. The epitaxial orientation relationships between the La0.7Sr0.3MnO3 LSMO and the sapphire was 111 LSMO/ / 0003 Al2O3 and 112̄ LSMO/ / 101̄0 Al2O3. A low field magnetoresistance LFMR of 12% was achieved at an external magnetic field of H=1 T at 77 K, possibly due to enhanced grain boundary effects. The postannealed film had columnar structures with well-crystallized large grains 200 nm , and showed a low resistivity and consequently negligible LFMR similar to that of single crystal LSMO. © 2006 American Institute of Physics. DOI: 10.1063/1.2197317