High-pressure dependent ferroelectric phase transition in lead titanate

Abstract

Ti K edge x-ray absorption near-edge structure (XANES) measurements across the pressure induced ferroelectric (FE)-paraeletric (PE) phase transition in PbTiO 3 a prototypical ferroelectric perovskite, are reported for the first time. A quantitative analysis of the XANES allows us to obtain the relative local displacement, directly related to the local electric polarization, of Ti and Pb atoms under pressure. In particular, we found that above the critical pressure, in the so-called cubic-paraelectric phase, the Ti atoms remain locally displaced from their cubic site indicating that this phase transition has in a general way an essential order-disorder component. However the magnitude of these local displacements is strongly affected by the applied pressure as opposed to what happens as a function of temperature. These conclusions have important consequences in the long standing controversial debate on the interpretation of the ferroelectric phase transition of PbTiO 3 , and related family compounds.

Zr-shift at the origin of the exceptional piezoelectric properties ofPbZr0.52Ti0.48O3

“…14͒ or no shift. 15 Additionally, although the Zr shift is found to be both temperature and composition independent, 14,16 the Ti shifts appear to have an orderdisorder component as a function of temperature 17 and pressure 18 which was found to be quite unusual for these ferroelectric displacive-type transitions. 19 This paper provides the evidence of the ferroelectric character of the Zratoms in PZT in the P-T space.…”

“…2 appears at pressures well above P C suggesting an order-disorder nature of the transition, as it has already been reported for Ti shifts in P-T space. 17,18 It is worth to stress that besides the displacement of Zr from the offset position to the centrosymmetric position of 0.06 Å, Let us now discuss about the XANES part of the spectra. The p-d peak, linked to the dipole transition, is expected to disappear at the ferroelectric-paraelectric transition as in PbTiO 3 .…”

Pressure dependent phase transitions in (Pb,Ca)TiO3: Determination of structure using high pressure synchrotron X-ray and Raman studies

“…With increasing demand for smarter ceramics, pressure dependent studies in some of these PbTiO 3 based ceramics have attained significance [24][25][26][27]. These investigations have not only provided the fundamental insight towards the pressure dependent phase transitions but have also increased the applicability of such ceramics [28][29][30][31]. One of the above mentioned ceramics viz., Pb 1-x Ca x TiO 3 has become subject for careful studies in recent times [17,18,21,32].…”

Glitch-free X-ray absorption spectrum under high pressure obtained using nano-polycrystalline diamond anvils

“…These spectroscopic techniques enable the investigation of pressure-induced changes in the local atomic structure, electronic structure and magnetic states of both the crystalline and the non-crystalline materials. After the development of perforated diamond anvils in order to reduce the X-ray absorption itself (Dadashev et al, 2001), the coverage of X-ray absorption experiments under high pressure extends to lower energies; highpressure research at the Ce L 3 -edge (5.723 keV) (Itié et al, 2005;Rueff et al, 2011) and Ti K-edge (4.966 keV) (Itié et al, 2006;Jaouen et al, 2007) have been reported.…”