Magnetic and electrical properties of coherently grown low-strain La0.7Ca0.3MnO3 films

La0.7Ca0.3MnO3 films have been grown epitaxially on NdGaO3 (110) substrates using pulsed laser deposition. Because of the very low nominal lattice mismatch with the substrate (less than or equal to0.12%) the films are under low epitaxial stress. The microstructure has been investigated by transmission electron microscopy, atomic force microscopy and X-ray diffraction. Coherently grown films with no detectable lattice defects (by our means) have been obtained. Their magnetic and resistive properties have been studied as a function of him thickness from 2 to 165 nm. The ferromagnetic transition temperature stays near the bulk value down to about 6 nm film thickness, and the spontaneous magnetization has a large value (similar to 85 emu/g) for all thicknesses (excluding the 2 nm film). Magnetic hysteresis loops show in-plane anisotropy that might still have a stress-induced contribution, with a [1 (1) over bar 0] easy and a [0 0 1] hard axis. The appearance of a semiconducting layer at the film surface or the interface with the substrate is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.