Colossal magnetoresistance of thin films of La 0.66Ba 0.33MnO 3 as a function of film thickness

Abstract

La 0.66Ba 0.33MnO 3 shows a strong change of its resistivity if a magnetic field is applied. The strength of this colossal magneto resistance (CMR) effect depends of the thickness of epitaxial thin films prepared on MgO (100) and SrTiO 3 (100). We have prepared films in a thickness range of 5 to 250 nm by pulsed laser deposition. The epitaxial La 0.66Ba 0.33MnO 3 thin films were characterized by Rutherford backscattering spectrometry and channeling, X-ray diffraction measurements as well as by high resolution transmission electron microscopy (HRTEM). The high crystalline quality was proved by ion channeling (minimum yield of χ min≈2%) and by HRTEM micrographs. By X-ray diffraction measurements, no additional phases were detected beside the cubic phase with a lattice constant a=3.915 Å. The CMR effect of 10 nm thin films is enlarged by 45% as compared to 150 nm thick films on MgO (100) substrates. The saturation magnetization decreases with decreasing film thickness.