Ferroelectrics

Ferroelectric Phase Transitions in Nano-Scale Chemically Ordered PbSc 0.5 Nb 0.5 O 3 Using a First-Principles Model Hamiltonian

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DOI:: 10.1080/00150190390222682

Umesh V. Waghmare^a, Eric J. Cockayne^b & Benjamin P. Burton^b

pages 187-196

Available online: 22 Jan 2011

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Effects of chemical order, disorder, short range order, and anti-phase boundaries on phase transitions and dielectric properties of PbSc 1/2 Nb 1/2 O 3 are studied through molecular dynamics simulations of a FP model. Simulations of large systems are required to capture these effects, and we present an efficient reciprocal space method, based on fast Fourier transforms, for calculating long-range interactions and inhomogeneous strain. Calculations for random or partially disordered systems yield significant increases in T = 0 K dielectric response, and broadening of the ferroelectric phase transition. Coupling between random fields caused by chemical disorder and the inhomogeneous strain (acoustic modes) affects the dynamics of soft modes in chemically nano-structured configurations.