Colossal magnetoresistance of thin films of La0.66Ba0.33MnO3 as a functionof film thickness

La0.66Ba0.33MnO3 shows a strong change of its resistivity if a magnetic fie ld is applied. The strength of this colossal magneto resistance (CMR) effec t depends of the thickness of epitaxial thin films prepared on MgO (100) an d SrTiO3, (100). We have prepared films in a thickness range of 5 to 250 nm by pulsed laser deposition. The epitaxial La0.66Ba0.33MnO3 thin films were characterized by Rutherford backscattering spectrometry and channeling, X- ray diffraction measurements as well as by high resolution transmission ele ctron microscopy (HRTEM). The high crystalline quality was proved by ion ch anneling (minimum yield of chi(min) approximate to 2%) and by HRTEM microgr aphs. By X-ray diffraction measurements, no additional phases were detected beside the cubic phase with a lattice constant a = 3.915 Angstrom. The CMR effect of 10 nm thin films is enlarged by 45% as compared to 150 nn thick films on MgO (100) substrates. The saturation magnetization decreases with decreasing film thickness. (C) 1998 Elsevier Science S.A. All rights reserv ed.