Strain Accommodation and Relaxation Mechanisms in Epitaxially Grown Manganites

Epitaxial growth of La 1-x (Sr or Ca) x MnO 3 manganites (LSMO or LCMO) has been successfully achieved on SrTiO 3 (001) and MgO(001) substrates. We report the influence of the deposition conditions, in particular growth rate, annealing and nature of the substrate, on the state of strain in the manganite layers. Fully strained layers are reported at very slow growth rate on SrTiO 3 substrates while misfit dislocations are clearly observed in layers grown on MgO and alsoin layers grown on SrTiO 3 , after annealing at high temperature. Besides, evidence is given for a rhombohedral (respectively orthorhombic) distortion relaxation in LSMO (respectively LCMO) layers. The microstructure of the manganite layers is analyzed taking into account their non-isomorphic growth on the cubic substrates.