Doping Effect on Crystal Structure of Fast Oxide Ion Conductor LaGaO_3-Based Perovskite Compounds

摘要

Doping effects of Sr and/or Mg on the crystal structures of LaGaO_3 perovskites were investigated. The doping with Mg into Ga-site in LaGaO_3 led to structural change from the orthorhombic primitive lattice (Pbnm) to the orthorhombic body-centered lattice (Ibmm) at room temperature. The orthorhombic cell {Ibmm) of LaGa_(0.9)Mg_(0.1)O_(2.95) changed to the monoclinic (12/a) by doping with Sr into La site. Neutron powder diffraction analyses revealed that these compounds had GaO_6 octahedral tilt. The GaO_6 octahedral tilt angles were reduced with doping with Sr and/or Mg.