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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. 55Mn nuclear magnetic resonance identifies the presence of localized Mn4+ states. Superconducting quantum interference device magnetization measures TN=131(3) K and a saturation moment μ=1.09μB/Mn, revealing a small concentration of Mn4+ and placing our films within the antiferromagnetic insulating phase. [ABSTRACT FROM AUTHOR]

In this paper, we illustrate an approach to discriminate between epitaxial strain and other factors responsible for the decrease of the metal–insulator transition temperature (TP) in thin La0.7Sr0.3MnO3 films grown by pulsed laser deposition. Using this approach, we have estimated the effect of the biaxial strain on TP. Ultrathin films, independent of epitaxial strain, do not show any metal–insulator transition over the full temperature range. This finding confirms the existence of an interface dead layer. The strain-independent decrease in TP, relative to its bulk value, observed for a much wider thickness range (up to about 1000 Å) can most likely be attributed to oxygen deficiency. [ABSTRACT FROM AUTHOR]

Abstract: In this article, we investigate the effects of oxygen partial pressure in the deposition chamber on the optical properties of zinc oxide (ZnO) thin films; in particular, we examine the variation of the refractive index with oxygen flux. ZnO thin films were deposited by radio-frequency (RF) magnetron sputtering and studied by means of X-ray diffraction (XRD) and spectroscopic ellipsometry (SE). We have found a preferential -axis growth of ZnO films, with slightly variable deposition rates from 2.6 to 3.8 Å/s. Conversely, the refractive index exhibits, from ultraviolet (UV) to near infrared (IR), a considerable and almost linear variation when the oxygen flux value in the deposition chamber varies from 0 to 10 sccm. [Copyright &y& Elsevier]

Abstract: Thin films of La0.67Ba0.33MnO3 were deposited on NdGaO3 by pulsed laser deposition with in situ RHEED diagnostics. A strong dependence of structural and electrical transport properties of the films on the background oxygen pressure was observed. Electrical resistance versus temperature and X-ray diffraction measurements were used to characterise the deposited films. Deposition at low background oxygen pressure (≈10−1 Pa) resulted in a good structural quality with an atomically flat surface, but poorer transport properties compared to films grown at higher pressure (≈50Pa). These observations have been correlated with the characteristics of the plume expansion by studying pulsed laser ablation of manganate samples into oxygen background gas by optical emission spectroscopy and ion probe diagnostics. These studies have been carried out using the parent LaMnO3 compound as target material in presence of an oxidizing atmosphere. [Copyright &y& Elsevier]