Magnetotransport properties of c-axis oriented La_(0.7)Sr_(0.3)MnO_3 thin films on MgO-buffered SiO_2/Si substrates

摘要

c-axis oriented La_(0.7)Sr_(0.3)MnO_3 (LSMO) films on MgO-buffered SiO_2/Si substrates were prepared, and their texture, microstructure, and magnetotransport properties were studied and compared to epitaxial LSMO/MgO (001) and polycrystalline LSMO/SiO_2/Si films. c-axis oriented MgO buffer layers were obtained on amorphous SiO_2 layer through rf sputter deposition at low substrate temperature and consequent postannealing processes. In situ pulsed laser deposition-grown LSMO films, deposited on the MgO layer, show strong c-axis texture, but no in-plane texture. The c-axis oriented LSMO films which are magnetically softer than LSMO/SiO_2/Si films exhibit relatively large low field magnetoresistance (LFMR) and sharper MR drop at lower field. The large LFMR is attributed to a spin-dependent scattering of transport current at the grain boundaries.