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)(Al2)O-3 and < 11 (2) over bar >(LSMO)//< 10 (1) over bar0 >(Al2O3). A low field magnetoresistance (LFMR) of similar to 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 (similar to 200 nm), and showed a low resistivity and consequently negligible LFMR similar to that of single crystal LSMO.(c) 2006 American Institute of Physics.