Neutron diffraction study on lanthanum gallate perovskite compounds

Abstract

In the present work, the crystal structures of perovskite-type lanthanum gallate compounds, LaGaO₃ and La_0.8Sr_0.2Ga_0.8Mg_0.2O_2.8 at room temperature were determined using neutron powder diffraction. The structures of LaGaO₃ and La_0.8Sr_0.2Ga_0.8Mg_0.2O_2.8 were in orthorhombic (Pbnm) and cubic (Pm-3m) phases, respectively. In the LaGaO₃ structure, the GaO₆ octahedron was tilted along the b and c axes. The tilt of GaO₆ octahedron was not observed in the La_0.8Sr_0.2Ga_0.8Mg_0.2O_2.8 which showed superior oxide ion conduction.