Growth and characterization of magnetoresistive La-Ca-Mn-O films on Si(100) and Si(111) substrates

In situ grown La-Ca-Mn-O films with (100), (110), and mixed orientations have been prepared by pulsed-laser deposition on YSZ-buffered Si(100) and Si(lll) substrates. X-ray diffractometry, magnetoresistance (MR), and magnetization of these films were measured. The best magnetoresistance was observed in the single-phase, epitaxial (110), and this structure was grown with the best quality on the YSZ(111)-buffered Si(lll) substrates. These films showed higher temperatures for the peak resistivity than those in the (100) films. In a magnetic field of 5 T, the maximum magnetoresistance of 250% and 164% occurred at 195 and 140 K, respectively, in the as-deposited (110) and (100) films. The MR behavior of these two orientations, as a function of the substrate temperature during La-Ca-Mn-O film growth and the orientation of the YSZ buffer layer, is discussed. (C) 1996 American Institute of Physics.