Figure 2
From: Pressure-induced reversal between thermal contraction and expansion in ferroelectric PbTiO3
(a) The pressure dependence of unit cell volumes of tetragonal PbTiO3 at different temperatures. (2b), the lattice volumes of tetragonal PbTiO3 as a function of temperature at constant pressures. The solid curves at 0.3 GPa, 0.8 GPa and 1.2 GPa are the data interpolated from Figure 2a. The plotted symbols are the experimental data points collected within ±0.1 GPa of the indicated pressures. The pink shadow area denotes the region of thermal contraction and the rest plain area corresponds to the region of thermal expansion. The ΔTEi represents the temperature range for expansion and ΔTCi the temperature range for contraction. The subscripts of 1, 2, 3 and 4 in ΔTEi and ΔTCi correspond to the pressures of 0 GPa, 0.3 GPa, 0.8 GPa and 1.2 GPa, respectively. The turnover points from expansion to contraction are 447 K at 0.3 GPa and 556 K at 0.8 GPa.
