title: High-temperature dielectric response of ferroelectric relaxors.
abstract: It has long been considered that polar nanoregions in relaxors form at Burns temperature T(d) ≈ 600K. High-temperature dielectric investigations of Pb(Mg(1/3)Nb(2/3)) O(3) (PMN) single crystal, PMN-PbTiO(3) ceramics, and (Pb,La) (Zr,Ti)O(3) ceramics reveal, however, that dielectric dispersion, detected around 600K, is due to the Maxwell-Wagner-type contributions of surface layers. The intrinsic response was analyzed in terms of the universal scaling, taking into account the asymptotic and the correction-to-scaling behavior, and the results imply much higher T(d) or formation of polar nanoregions in a broad temperature range. High values of the dielectric constant indicate, however, that polar order already exists at the highest measured temperatures of 800K. The obtained critical exponents indicate critical behavior associated with universality classes typically found in spin glasses.
authors.affiliation: Jožef Stefan Institute, Ljubljana, Slovenia. vid.bobnar@ijs.si
authors.forename: Vid
authors.initials: V
authors.lastname: Bobnar
authors.forename: Andreja
authors.initials: A
authors.lastname: Erste
authors.forename: Urska
authors.initials: U
authors.lastname: Gradisar
authors.forename: Cene
authors.initials: C
authors.lastname: Filipic
authors.forename: Adrijan
authors.initials: A
authors.lastname: Levstik
authors.forename: Zdravko
authors.initials: Z
authors.lastname: Kutnjak
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003198:Computer Simulation; D004553:Electric Conductivity; D006358:Hot Temperature; D060526:Magnetic Fields; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*