Poling effect on distribution of quenched random fields in a uniaxial relaxor ferroelectric

TL;DR

This study investigates how poling affects the distribution of quenched random electric fields in a relaxor ferroelectric, revealing that poling reduces field dispersion and aligns experimental results with a new theoretical model.

Contribution

The paper introduces a novel mechanism explaining the impact of poling on random electric field distribution in relaxor ferroelectrics, supported by numerical simulations.

Findings

Poling reduces the dispersion of quenched random electric fields.

Numerical simulations agree with experimental polarization measurements.

The proposed model challenges previous explanations of random field compensation.

Abstract

The frequency dependence of the dielectric permitivity's maximum has been studied for poled and unpoled doped relaxor strontium barium niobate $Sr_{0.61}Ba_{0.39}Nb_{2}O_{6}:Cr^{3+}$ (SBN-61:Cr). 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 {\bf 92}, 065701 (2004)].