The Polar Nano Regions $\rightleftharpoons$ Relaxor Transition in $P{b}_{1-X}(S{c}_{1/2}N{b}_{1/2})O_{3-X}$; $X$ = bulk concentration of nearest neighbor [Pb-O] divacancies

Abstract

In previous work, molecular dynamics simulations based on a first-principles-derived effective Hamiltonian for $P{b}_{1-X}(S{c}_{1/2}N{b}_{1/2})O_{3-X}$~ (PSN), with nearest-neighbor Pb-O divacancy pairs, was used to calculate $X_{[\mathrm{Pb}-\mathrm{O}]}$~vs.~T, phase diagrams for PSN with: ideal rock-salt type chemical order; nanoscale chemical short-range order; and random chemical disorder. Here, we show that the phase diagrams should include additional regions in which a glassy relaxor-phase (or state) is predicted. With respect to phase diagram topology, these results strongly support the analogy between relaxors and magnetic spin-glass-systems.