High pressure study of ScAlO3 perovskite

Abstract The crystal structure of orthorhombic (Pbnm) ScAlO3 perovskite has been refined to 5 GPa using single-crystal X-ray diffraction. The compression of the structure if anisotropic with βa=1.39(3)×10−3 GPa−1, βb=1.14(3)×10−3 GPa−1 and βc=1.84(3)×10−3 GPa−1. The isothermal bulk modulus of ScAlO3, KT, determined from fitting a Birch-Murnaghan equation of state (K′T=4) to the volume compression data is 218(1) GPa. The interoctahedral angles to not vary significantly with pressure, and the compression of the structure is entirely attributable to compression of the AlO6 octahedra. The compressibilities of the constituent AlO6 and ScO12 are well matched: βAl−O=1.6×10−3 GPa−1 and βSc−O=1.5×10−3 GPa−1. Therefore the distortion of the structure shows no significant change with increasing pressure.