Pressure induced phase transition of PbNiO3 from LiNbO3-type to perovskite

• Phase transition of PbNiO3 from LiNbO3-type to perovskite-type occurred between 4.4 and 9.5 GPa in the compression process.
• The compression behavior of lattice parameters of the LiNbO3-type and perovskite-type PbNiO3 has also been analyzed.
• The equation of state (EOS) at room temperature of the two types of PbNiO3 has been acquired.

The phase transition of PbNiO3 from LiNbO3 structure to the perovskite structure has been observed between 4.4 and 9.5 GPa, which was investigated by high-pressure synchrotron x-ray powder diffraction at room temperature. Compression behavior of the two phases has been analyzed, and the c axis is the soft direction for LiNbO3-type PbNiO3. The bulk modulus of the LiNbO3-type PbNiO3 is K0=184(3) GPa, K0′=4.5(9), and the perovskite type is K0=166(8) GPa, K0′=4.9(8).