Low field magnetotransport properties of (La _0.7Sr _0.3MnO ₃) _0.5: (ZnO) _0.5 nanocomposite films

(La0.7 Sr0.3 Mn O3) 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 La0.7 Sr0.3 Mn O3 (LSMO) and the sapphire was (111)LSMO (0003) Al2 O3 and 〈11 2- 〉LSMO 〈10 1- 0〉 Al2 O3. 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.