W LIII-edge XANES and EXAFS studies of Pb(Fe2/3W1/3)O3-PbTiO3 multiferroic ceramics

The local structure of Pb(Fe2/3W1/3)O3 (PFW) and Pb(Fe2/3W1/3)O3-PbTiO3 (PFW100xPT, x=0.10 and x=0.20) multiferroic ceramics was probed by X-ray absorption spectroscopy at the W LIII-edge. The analysis of XANES spectra did not show significative modifications in the intensity or energy of transitions as a function of temperature or PbTiO3 content. The fitting of EXAFS spectra of PFW samples revealed a local rhombohedral symmetry of W atoms around 120 K, which is consistent with the electrical properties of this compound. Concerning the local structure of W atoms in PFW100xPT samples, in all cases, at 290 K, a local tetragonal symmetry was determined although by X-ray diffraction a cubic local symmetry was expected.