Interface Structure And Strain Relaxation In Nd0.96mno3 Epilayers Grown On (001) Srtio3 Substrates

In this work we focus on the growth of highly oriented Nd0.96MnO3 (NMO) pemvskite epilayers of different thickness on single-crystalline (001)SrTiO3 (STO) template, using an injection metalorganic chemical vapor deposition process. X-ray diffraction revealed that the epilayers have an orthorhombic Pnma structure and were purely (((1) over bar 01) oriented parallel to the (001) plane of the substrates. The orientation relationships between the film and substrate are rather well defined in the vicinity of the interface as [(1) over bar 01] NMO//[001]STO (out-of-plane), [101]NMO// [100] STO and [010]NMO//[010]STO (in plane). It can be concluded that the film thickness significantly influences the strain state of the NMO epilayers deposited on STO. There was a contraction of out-of-plane layer network spacing leading to a progressive relaxation in the growth direction. The out-of-plane lattice parameter is lower than the bulk value. As the film thickness increases, the NMO epilayer strain reduces so that out-of-plane lattice parameters tend towards their bulk values. The calculated strain goes from - 0.4%(thickness of 150 nm) to 0% (thickness of 600 nm). These epilayers are therefore strained at the interface and relax with the thickness. The out-of-plane lattice parameter observed for the 600 nm thick epilayer relaxed toward the bulk NMO. No traces of extra phases are detected. An atomic model of interfaces has been built using cross-sectional transmission electron microscopy image, as well as a crystallographic simulation software CrystalMaker.