Incorporation of Monovalent Ions in ZnO and Their Influence on Varistor Degradation

Abstract

An atomistic simulation technique has been used to predict the spatial arrangement of the dopant species sodium, lithium, and chlorine within the zinc oxide lattice. The alkaline oxides are preferentially incorporated via a self-compensating mode, forming interstitial cations which hinder the migration of zinc interstitials and hence slow the degradation of the varistor. The addition of chloride ions is shown to negate this effect by forming sodium and chloride substitutional defects rather than any species involving sodium interstitial ions.

Computational study of the energetics of charge and cation mixing in U1−xCexO2Hanken1, Stanek2, Grønbech‐Jensen3 et al. 2011Phys. Rev. B370251View full textAdd to dashboardCite

“…The Buckingham, charge and spring-constant parameters are given in Refs. [17][18][19][20] for the O 2− , U 4+ , Ce 3+ and Ce 4+ ions, and are reproduced in Table II for reference. Also included in Table II are potential parameters for the U 5+ ion developed by one of us previously 39 .…”

“…Based on the results of the DFT+U calculations we fit the difference in electron binding energies of U 5+ and Ce 4+ ions in the fluorite structure. With this parameter, and previously published potential models [17][18][19][20] for U 4+ , Ce 4+ , Ce 3+ , and O 2− , we perform supercell calculations to investigate the enthalpy and entropy of mixing of disordered urania-ceria solid solutions. Details of the computational approaches are described in the next section, and relevant results from the DFT+U and classical-potential model calculations are then presented in Section III.…”

Effect of load triaxiality on polymorphic transitions in zinc oxide

“…The MD simulations use the Buckingham potential with charge interactions (Binks and Grimes, 1993;Wolf et al, 1999). The calculations concern the quasi-static uniaxial tension of nanowires with the ½01 10 growth orientation and nanorods with the [0 0 0 1] growth orientation and the hydrostatic compression of bulk ZnO.…”

Atomistic simulation of CeO2 surface hydroxylation: implications for glass polishing

“…Short-range interactions are described by the Buckingham potential [33]. The potential parameters for Ce 4+ -O 2-and O 2--O 2-can be found in the papers where the original derivation is described ( [3] and [34], respectively). Dipoles can be of great significance at surfaces.…”

“…In addition to the movement of ions, dipoles will also be formed through the displacement of charge around a single ion (i.e., polarization). Here such effects are included by using a core/shell model [35] and the shell parameters are available in the original papers [3,34].…”