Random-Site Cation Ordering and Dielectric Properties of PbMg1/3Nb2/3o3-PbSc1/2Nb1/2o3

TL;DR

This study investigates the cation ordering and dielectric properties of PMN-PSN solid solutions, revealing how compositional changes influence relaxor behavior and domain structures, with implications for material design.

Contribution

It provides new insights into the relationship between cation ordering, dielectric behavior, and composition in PMN-PSN crystals using X-ray analysis and dielectric measurements.

Findings

Ordered domains are ~50 nm in size.

Relaxor-like dielectric behavior persists for x < 0.6.

Dielectric permittivity maximum diffusion is lowest at x=0.6.

Abstract

(1-x)PbMg1/3Nb2/3O3-(x)PbSc1/2Nb1/2O3 (PMN-PSN) solid solution crystals have been grown by the flux method in the whole concentration range. X-ray supercell reflections due to B-cation ordering were observed for as-grown crystals from the 0.1 < x < 0.65 compositional range. Though the ordered domains are rather large (~50 nm) the relaxor-like dielectric behavior is observed for compositions with x < 0.6. The diffusion of the dielectric permittivity maximum in as-grown crystals is the lowest at x = 0.6 and increases towards the end members of solid solution. Such behavior is explained within a Bragg-Williams approach by employing the random layer model. At x ~ 0.6 the excitation energy determined from the Vogel-Fulcher relation exhibits a jump which we regard to changing the kind of the polar regions from PbMg1/3Nb2/3O3 to PbSc1/2Nb1/2O3 related type.