Exploring the phase transition of BiNbO4: A high pressure x-ray diffraction study

In the present work, the orthorhombic (α) BiNbO4 have been investigated with the in-situ angle-dispersive x-ray diffraction (ADXRD) measurements under high pressure. Pressure-induced phase transition was observed in α-BiNbO4, and compressibility of the unit cell axes (a, b and c axes) of α-BiNbO4 shows an anisotropic with pressure increasing. The phase transition routine and the effect of pressure in the phase evolution of BiNbO4 were also explored. The results indicate that pressure-induced phase transition is reversible, in contrast, pressure and temperature-induced phase transition is irreversible in system of BiNbO4, but the phase remains stable without pressure. High pressure plays a critical role and provides a driving force for phase transition of BiNbO4.