Molecular dynamics study of oxygen diffusion in Pr(2)NiO(4+delta)

Phys Chem Chem Phys. 2010 Jul 7;12(25):6834-6. doi: 10.1039/c001809k. Epub 2010 May 11.

Abstract

Oxygen transport in tetragonal Pr(2)NiO(4+delta) has been investigated using molecular dynamics simulations in conjunction with a set of Born model potentials. Oxygen diffusion in Pr(2)NiO(4+delta) is highly anisotropic, occurring almost entirely via an interstitialcy mechanism in the a-b plane. The calculated oxygen diffusivity has a weak dependence upon the concentration of oxygen interstitials, in agreement with experimental observations. In the temperature range 800-1500 K, the activation energy for migration varied between 0.49 and 0.64 eV depending upon the degree of hyperstoichiometry. The present results are compared to previous work on oxygen self-diffusion in related K(2)NiF(4) structure materials.