Molecular dynamics study of oxygen diffusion in Pr2NiO4+δ

Abstract

Oxygen transport in tetragonal Pr₂NiO_4+δ has been investigated using molecular dynamics simulations in conjunction with a set of Born model potentials. Oxygen diffusion in Pr₂NiO_4+δ 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 K₂NiF₄ structure materials.