Molecular dynamics simulation of superionicity in neighborite, NaMgF₃

Authors

L. X. Zhou, University of Nebraska - Lincoln
J. R. Hardy, University of Nebraska - LincolnFollow
H. Z. Cao, University of Nebraska - Lincoln

Date of this Version

1997

Citation

GEOPHYSICAL RESEARCH LETTERS, VOL. 24, NO. 7, PAGES 747-750, APRIL 1, 1997

Comments

Copyright 1997 by the American Geophysical Union.

Abstract

Superionicity in neighborite, NaMgF₃, has been studied by molecular dynamics using parameter free Gordon-Kim potentials. These simulations show that this halide-based perovskite has a superionic phase. The onset temperature for superionicity is ~50-100 K below the melting point. This is a novel type of superionicity in a halide, occurring as it does in a perovskite rather than a fluorite. Superionicity is demonstrated to occur whether one uses the full ionicity for Mg ²⁺ and F^- or employs reduced charges derived from a Quantum Chemistry calculation. The relevance of these findings to predictions of superionicity in the oxide perovskite MgSiO₃ [Matsui and Price, 1991] is discussed