Structure and microstructure of La1-xSrxMnO3 (x approximate to 0.16) filmsgrown on a SrTiO3 (110) substrate

The interface between La1-xSrxMnO3 (LSMO) epitaxial films grown by pulsed-l aser deposition on the (110) surface of a SrTiO3 single-crystal substrate h as been investigated by high-resolution electron microscopy and by electron -energy-loss spectroscopy. The structure of the LSMO films is rhombohedral, a pseudocubic distortion of the perovskite structure. The films show micro twinning, which apparently acts as a mechanism of misfit strain relaxation without a need for the formation of interfacial dislocations. The interface exhibits corrugations formed by mutually perpendicular microfacets paralle l to the cubic planes of the pseudocubic structure. Within the LSMO film, c lose to the interface, inclusions are formed; their lattice is coherent wit h that of the surrounding LSMO matrix. Energy-electron-loss spectroscopy su ggests that the inclusions are lanthanum rich. A film growth scenario compa tible with the observed phase separation is proposed.