Phase transitions in Sr0.61Ba0.39Nb2O6:Ce3+: I. Susceptibility of clusters and domains
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
Published online: 15 April 2000
The complex dielectric susceptibility of Sr0.61Ba0.39Nb2O6:Ce3+ (SBN61:Ce) has been measured at frequencies 102≤f≤107HZ 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.
PACS: 64.70.Pf – Glass transitions / 77.22.Ch – Permittivity (dielectric function) / 77.80.-e – Ferroelectricity and antiferroelectricity / 77.84.Dy – Niobates, titanates, tantalates, PZT ceramics etc.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000