PAC investigation in the Zr-rich region of the PZT phase diagram

R. E. ALONSO; A.P. AYALA; A. LÓPEZ GARCÍA; J. A. EIRAS

La Plata, Argentina

Congreso; 35th Anniversary of the Hyperfine Interactions at La Plata; 2005

CONICET

<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:ES; mso-fareast-language:ES;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt;} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 85.05pt 70.85pt 85.05pt; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->   Lead titanate zirconate or PZT (PbZr1-xTixO3) is one of the most intensively studied ferroelectric materials mainly due to its technological applications. Along time, PZT was subject of many experimental and theoretical research efforts. This system presents an interesting concentration-temperature (x-T) phase diagram and its physical properties can be associated to the several structural modifications found in it. The x-T phase diagram determined by in the early times by Jaffe et al. presents a variety of phase transitions among ferroelectric, antiferroelectric and paraelectric phases. In that diagram, two regions are remarkable. One of them is the well-known as Morphotropic Phase Boundary (MPB), where PZT exhibits outstanding ferroelectric properties. The recent discovery of a monoclinic phase close to MPB has provided a new light on these properties and several works has been published up to now. The other interesting region is the Zr-rich PZT, that up to x = 0.06 involves four phases. Two of them are antiferroelectric, with orthorhombic and tetragonal symmetries and two are ferroelectric with trigonal symmetries. Previous results using TDPAC spectroscopy show that above 10% PZT, the probe occupy two highly distributed sites, whereas PbZrO3 is characterized by a single site with a very well defined hyperfine interaction. The aim of this work is to investigate the Zr-rich region of the PZT phase diagram in order to correlate the hyperfine parameters with the antiferroelectric-ferroelectric phase transition observed around 5%.