Equation of state of BaTiO3 and KNbO3 at room temperature up to 30GPa

Equation of state of nanocrystalline BaTiO3 up to 52 GPa at room temperature

“…The transition pressure agrees fairly well with values reported by other investigators using X-ray and other experimental techniques such as Raman, electrical and photo acoustic measurements [13][14][15][23][24][25]. On analysing the diffraction spectra of nanoBaTiO 3 at different pressures, despite the peak broadening due to the nanosize, we were able to clearly notice the tetragonal splitting in the diffraction lines even at 3.4 GPa between two theta angles 16 to 24 degrees as shown in Fig.…”

“…The pressure-volume data fitted by constraining B 0 ′ = 4, yielded a bulk modulus of 179(3) GPa for bulk BaTiO 3 and 191(4) GPa for nanoBaTiO 3 . The bulk modulus obtained in our experiments for bulk BaTiO 3 is comparable with earlier works [13,14]. The values of bulk modulus obtained for nanoBaTiO 3 are much lower than values reported from measurements on 50 nm material [15].…”

“…Pruzan et al [13] reported the equation of state of bulkBaTiO 3 up to 30 GPa by angle dispersive X-ray diffraction, following an early X-ray work on the BaTiO 3 single crystal by Milinowsky et al [14]. More recently, Li FengYing et al [15] have studied different particle sizes of nanoBaTiO 3 ranging from 10-200 nm with energy dispersive (EDXRD) technique at ambient temperature and reported an increase in the phase transition pressure with decrease in grain size.…”

Structural properties of PbVO3perovskites under hydrostatic pressure conditions up to 10.6 GPa

“…Table 2 lists the bulk moduli of several compounds with a perovskite structure. We found that the bulk modulus of the PbVO 3 T-phase is comparable to that of the BiCoO 3 T-phase [18] but much smaller than that of PbTiO 3 [39] and BaTiO 3 [17]. These differences in the bulk moduli can be interpreted in terms of the degree of tetragonal distortion.…”

“…The phase transition from tetragonal to cubic perovskite in PbVO 3 mainly involves the displacement of atoms in the c-direction, showing no distinct change in atomic packing (see figure 1). Therefore, the phase transition can be taken as a displacive phase transition that occurs in typical ferroelectric perovskite materials such as PbTiO 3 and BaTiO 3 [15,17]. However, unlike typical displacive phase transitions, the T-to-C transition in PbVO 3 perovskites is a sluggish process with a broad pressure range for two-phase coexistence (2.7-6.4 GPa), which is probably intrinsic to the phase transition as a hydrostatic pressure medium was used in the present work.…”