Magnetoresistance of La 0.7Ca 0.3MnO 3 thin film biepitaxial step junctions

Abstract

The biepitaxial La 0.7Ca 0.3MnO 3 (LCMO) thin films grown on SrTiO 3 substrates using a buffer layer of anatase TiO 2 were fabricated. The magnetoresistance (MR) of biepitaxial step junction (BSJ) across the boundary layer of biepitaxial LCMO (0 0 1) and LCMO (1 1 0) film was investigated. The temperature and field dependence of MR for BSJ are qualitatively similar to those obtained in other type of artificial grain boundaries with a comparable MR ratio at low temperatures. However, the observed linear current–voltage characteristic across BSJ is in sharp contrary to the commonly reported non-ohmic characteristics. The results are consistent with features predicted by the model of spin-dependent transport across a depressed magnetic ordering and metallic-like junction layer.