Crystal structures of ferroelectric phases FR(LT)/FR(HT) in PbZr0.75Ti0.25O3solid solutions and their dependence on temperature

Abstract

The structure of rhombohedral PbZr_0.75Ti_0.25O₃ has been refined at liquid nitrogen and room temperatures (low temperature form) and at 105°C (high temperature form) using neutron diffraction data. Rotations of oxygen octahedra, characteristic for the low temperature phase, amount to ±5.3 and ±3.2 degrees for the former two temperatures and vanish at 95°C. Cation shifts which make the crystal ferroelectric are not markedly changed at the phase transition. At the three temperatures they vary between 0.49–0.40 Å for Pb and 0.17–0.11 Å for Zr/Ti.