Temperature-Dependent Behavior of PbSc1/2Nb1/2O3 From First Principles
Eric J. Cockayne, Benjamin P. Burton, L Bellaiche
We study the ferroelectric phase transition in PbSc1/2Nb1/2O3 (PSN) using a first-principles effective Hamiltonian approach. Results for PSN with NaCl-type ordering of Sc and Nb on the B sites shows that a Pb-centered effective Hamiltonian is appropriate for the ordered cell. We obtain a complete effective Hamiltonian for ordered PSN that has the form of effective Hamiltonians for simple perovskites. We modify the effective Hamiltonian to include the effects of Sc-Nb disorder by adding one additional term giving the effective force on the Pb site due to the nearest neighbor B-site cations. Monte Carlo simulations of our model shows that disordered PSN has a lower Curie temperature than ordered PSN, in agreement with a previous first-principles study based on a virtual crystal approach. No evidence for relaxor behavior is seen in our model.
Workshop on Fundamental Physics of Ferroelectrics | 11th | Fundamental Physics of Ferroelectrics 2001: 11th Williamsburg Workshop
, Burton, B.
and Bellaiche, L.
Temperature-Dependent Behavior of PbSc<sub>1/2</sub>Nb<sub>1/2</sub>O<sub>3</sub> From First Principles, Workshop on Fundamental Physics of Ferroelectrics | 11th | Fundamental Physics of Ferroelectrics 2001: 11th Williamsburg Workshop
(Accessed February 21, 2024)