Transport and magnetic anisotropy in CMR thin film La_{1-x}Ca_{x}MnO_{3} (x \approx 1/3) induced by a film-substrate interaction

Abstract

We present a study of anisotropy of transport and magnetic properties in La_{1-x}Ca_{x}MnO_{3} (x \approx 1/3) film prepared by pulsed-laser deposition onto a LaAlO_{3} sunstrate. We found a non-monotonic dependence of magnetoresistance (MR) on magnetic field H for both H perpendicular and parallel to the film plane but perpendicular to the current. This rather complex behavior of MR manifests itself at low temperatures, far below the Curie temperature. Two main sources of MR anisotropy have been considered in the explanantion of the results: (1) the existence of preferential directions of magnetization (due to strains stemming from the lattice film-substrate mismatch or other reasons); (2) dependence of resistance on the angle between current and the magnetization, which is inherent in ferromagnets.