Large low-field magnetoresistance observed in twinned La 2/3Ca 1/3MnO 3thin films epitaxially grown on yttria-stabilized zirconia-buffered silicon on insulator substrates

Abstract

La 2/3Ca 1/3MnO 33 thin films have been grown on yttria-stabilized zirconia (YSZ) buffered silicon-on-insulator (SOI) substrates by the pulsed laser deposition technique. While full cube-on-cube epitaxy was achieved for the YSZ layer, the top manganite layer was multioriented in plane, with a coexistence of cube-on-cube and cube-on-diagonal epitaxial structures. Due to a combined influence from the magnetocrystalline, shape, and stain-induced magnetic anisotropy, in zero field and low temperatures the local spin orientation varies across the large-angle grain boundaries. As a result, a quite large low-field magnetoresistance (LFMR) based on spin-dependent tunneling was observed. The film shows a resistance change of ∼20% in a magnetic field