In-situ high pressure X-ray diffraction studies of orthoferrite SmFeO 3

The high-pressure behaviors of SmFeO3 are investigated by angle-dispersive synchrotron X-ray powder diffraction under a pressure of up to 40.3 GPa at room temperature. The crystal structure of SmFeO3 remains stable at up to the highest pressure. The different pressure coefficients of the normalized axial compressibility are obtained to be βa = 0.60 × 10−3 GPa−1, βb = 0.79 × 10m3 GPa−1, βc = 1.28 × 10−3 GPa−1, and the bulk modulus (B0) is determined to be 293(3) GPa by fitting the pressure-volume data using the Birch—Murnaghan equation of state. Furthermore, the larger compressibility of the FeO6 octahedra suggests the evolution of the orthorhombic structure towards higher symmetry configuration at high pressures.