https://doi.org/10.1007/s100510051072
Phase transitions in Sr0.61Ba0.39Nb2O6:Ce3+: II. Linear birefringence studies of spontaneous and precursor polarization
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,
49069 Osnabrück, Germany
Received:
1
October
1999
Published online: 15 April 2000
The linear birefringence (LB) of 
(SBN61:Ce) has been measured as a function of temperature within the range of
. Large tails have been observed above
the ferroelectric phase transition temperatures 
, 328, 320
and 291 K for the concentrations x = 0, 0.0066, 0.0113 and 0.0207,
respectively. Within an Ornstein-Zernike analysis the critical exponents γ,
ν and β are determined. It suggests that pure SBN61 belongs to the 3D Ising
universality class. Doping with 
ions, which seem to act as
random fields, enhances the relaxor properties. The critical exponents γ
and ν of SBN61:Ce shift against those of the three-dimensional
random-field Ising model.
PACS: 64.60.Fr – Equilibrium properties near critical points, critical exponents / 77.80.Bh – Phase transitions and Curie point / 77.84.Dy – Niobates, titanates, tantalates, PZT ceramics, etc.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
