Pressure-induced phase transition and octahedral tilt system change of Ba2BiSbO6

摘要

High-resolution X-ray synchrotron powder diffraction studies under high-pressure conditions are reported for the ordered double perovskite Ba2BiSbO6. Near 4 GPa, the oxide undergoes a pressure-induced phase transition. The symmetry of the material changes during the phase transition from space group R (3) over bar to space group I2/m, which is consistent with a change in the octahedral tilting distortion from an a(-)a(-)a(-) type to a(o)b(-)b(-) type using the Glazer notation. A fit of the volume-pressure data using the Birch-Murnagaham equation of state yielded a bulk modulus of 144(8) GPa for the rhombohedral phase. (C) 2005 Elsevier Inc. All rights reserved.