A variational approach to surface cation segregation in mixed conducting perovskites
作者： David S. Mebane
DOI: 10.1016/J.COMMATSCI.2014.11.025
关键词: Materials science 、 Perovskite (structure) 、 Chemical physics 、 Free surface 、 Dopant 、 Phase transition 、 Wetting 、 Spinodal 、 Computational chemistry 、 Solid surface 、 Nanometre
摘要: A variational, phase-field methodology describing the segregation of dopant cations to free surfaces mixed conducting perovskite oxides is introduced. Based on Cahn–Hilliard formalism for solute in alloys and Cahn theory wetting a solution at solid surface, model qualitatively predicts experimentally observed behavior oxides, which shows layers order tens nanometers. Critical this description are interactions among defects gradient energy – two related concepts that can be expected become influential relatively high concentrations. The analysis first-order phase transition surface-mediated spinodal may occur depending strength affinity oxygen vacancies surface.
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