Eur. Phys. J. B 14, 627-632 (2000)
https://doi.org/10.1007/s100510051071

Phase transitions in Sr_0.61Ba_0.39Nb₂O₆:Ce³⁺: I. Susceptibility of clusters and domains

¹ Laboratorium für Angewandte Physik, Gerhard Mercator-Universität, 47048 Duisburg, Germany
² Institut für Kristallographie, Zülpicher Straße 49b, Universität zu Köln, 50674 Köln, Germany
³ Fachbereich Physik, Universität Osnabrück, 49076 Osnabrück, Germany

Received: 1 October 1999
Published online: 15 April 2000

Abstract

The complex dielectric susceptibility of Sr_0.61Ba_0.39Nb₂O₆:Ce³⁺ (SBN61:Ce) has been measured at frequencies 10²≤f≤10⁷H_Z and temperatures 300≤T≤470K before and after poling. The relaxor behaviour with large polydispersivity observed above the ferroelectric phase transition temperature, Tc=360 and 340 K for x(Ce)=0 and 0.0066, respectively, is perfectly modeled within the framework of Chamberlin's dynamically correlated domain approach. Below Tc the dynamic nanodomain state crosses over into a ferroelectric state with polydispersive domain wall dynamics at very low frequencies. Presumably SBN61:Ce belongs to the three-dimensional random field Ising rather than to the dipole glass universality class.