Epitaxial stabilization of SmNiO3 films on (001) SrTiO3 substrates

The epitaxial stabilization of SmNiO3 (SNO) films grown by an injection MO-CVD process on ( 0 0 1) SrTiO3 (STO) substrates is discussed. By means of high-resolution x-ray diffraction, we show for the first time that SNO can be stabilized on STO with a minor amount of secondary phases and with a layer thickness reaching several hundreds of nanometres. It is argued that this stabilization is achieved because the lattice mismatch between these two perovskites is not as high as expected (1.8% instead of 2.8%). Moreover, the well-known dissociation of the SNO phase into NiO and Sm2O3 has been clearly correlated with the relaxation of epitaxial strain which is driven by the formation of misfit dislocations.