Room and high temperature structure of La1_xNdxGaO3 (x=0.27 and 0.37) perovskites determined by synchrotron powder Xray diffraction

High-resolution X-ray powder diffraction using synchrotron radiation has been used to determine the structure of La1 ?xNdxGaO3 (x=0.37 and 0.27) perovskites at room temperature, 1040 K and 1140 K respectively. Both crystals at roomtemperature, and La0.63Nd0.37GaO3 at 1040 K have the GdFeO3-type of structure (Pbnm space group, Z=4) whereas the La0.73Nd0.27GaO3 crystal at 1140 K has rhombohedral symmetry (R-3c space group, Z=6) with lattice parameters a= 5.55232(6) ? and c=13.4806(2) ?. Changes of the structure induced by the neodymium substitution and high temperatures in the La1?xNdxGaO3 perovskites are analyzed and discussed.