Preparation and characterization of LaMnO3 thin films grown by pulsed laser deposition

We have grown LaMnO3 thin films on (001) LaAlO3 substrates by pulsed laser deposition. X-ray diffraction confirms that the films are only slightly relaxed and are oriented square on square relative to the substrate. The measured Raman spectra closely resemble that observed in bulk LaMnO3, which indicates no relevant distortions of the MnO6 octahedra induced by the epitaxial strain. Therefore, no detectable changes in the lattice dynamics occurred in our LaMnO3 strained films relative to the bulk case. Mn-55 nuclear magnetic resonance identifies the presence of localized Mn4+ states. Superconducting quantum interference device magnetization measures T-N=131(3) K and a saturation moment mu=1.09 mu(B)/Mn, revealing a small concentration of Mn4+ and placing our films within the antiferromagnetic insulating phase. (c) 2006 American Institute of Physics.