Poling effect on distribution of quenched random fields in a uniaxial relaxor ferroelectricM. I. Marqués and C. Aragó
Departamento de Física de Materiales C-IV, Universidad Autónoma de Madrid 28049 Madrid, Spain
received 22 February 2005; accepted 2 May 2005
published online 1 June 2005
The frequency dependence of the dielectric permittivity's maximum has been studied for poled and unpoled doped relaxor strontium barium niobate : (SBN-61:). In both cases the maximum found is broad and the frequency dispersion is strong. The present view of random fields compensation in the unpoled sample is not suitable for explaining this experimental result. We propose a new mechanism where the dispersion of quenched random electric fields, affecting the nanodomains, is minimized after poling. We test our proposal by numerical simulations on a random field Ising model. Results obtained are in agreement with the polarization's measurements presented by Granzow et al. (Phys. Rev. Lett. 92 (2004) 065701).
77.80.Bh - Phase transitions and Curie point.
77.80.-e - Ferroelectricity and antiferroelectricity.
64.60.Fr - Equilibrium properties near critical points, critical exponents.
© EDP Sciences 2005