Magnetoresistive anisotropy and strain relaxation in oxygen deficient La0.65Ca0.35MnO3-δ films near the metal-insulator transition

The magnetoresistance (MR) and the "out-of-plane" magnetoresitive anisotropy (AMR(out)) peaks were measured in vacuum annealed La0.65Ca0.35MnO3-delta films across the metal-insulator transition. The measurements were performed for a very small increase in oxygen deficiency delta, which leads not only to an increase of resistivity but also to a decrease of the magnitude of both the AMR(out) and MR peaks. The decrease of the MR and AMR(out) peaks is attributed to the epitaxial strain relaxation resulting from thermal treatment. These properties could originate from the lattice strain in agreement with a recent model of strain-induced metal-insulator phase coexistence in manganites. (c) 2006 American Institute of Physics.