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MM: Fachverband Metall- und Materialphysik

MM 6: Transport in Materials: Ion, Charge and Heat Transport

MM 6.4: Vortrag

Montag, 27. März 2023, 11:00–11:15, SCH A 118

Understanding Oxide Ion Transport In Yttria Stabilized Zirconia: Fresh Insights from Molecular Dynamics Simulations — •Sudeshna Madhual, Krishnanjan Pramanik, and Padma Kumar Padmanabhan — Indian Institute of Technology Guwahati, Guwahati, Assam, India, 781039

A comprehensive molecular dynamics investigation of yttria stabilized zirconia,Y x Zr 1x O 2x/2 , is carried out for a wide range of compositions, x = 4 to 40 mol%, and over temperatures spanning 800 - 2200 K. The lattice parameter of the fluorite cell shows a monotonic increase with concentration, while the self-diffusivity of oxide ion as well as the resulting ionic conductivity, shows an optimum value around x = 10 mol%. These gross structural and transport properties of the system from the present study is in good agreement with previous experimental and theoretical investigations. It is noted that the oxygen migration occurs along straight channels parallel to the crystallographic axes, connecting the tetrahedral holes of the fluorite lattice occupied by them. A microscopic investigation of distinct oxygen environments, variably coordinated to Y 3+ and Zr 4+ cations, and of the channels connecting them is carried out. Analysis of these local channels for their energetics and their contribution to overall oxygen transport, resolved in terms of the cationic edges connecting them, provides fresh insights on the oxygen migration mechanism in the system.