Elastic Properties of Yttrium-Doped BaCeO3 Perovskite

J. Zhang, Y. Zhao, H. Xu (Los Alamos National Laboratory), B. Li, D.J. Weidner (Stony Brook University), and A. Navrotsky (UC Davis)

The variation of elastic properties with oxygen vacancies, a fundamental problem in solid-state science as well as in materials design and application, has not been well understood by either experiments or theory. We studied the elasticity of the oxygen-deficient BaCe1-xYxO3-0.5x perovskite with x = 0.00 and 0.15 using ultrasonic interferometry and synchrotron x-ray diffraction. Our results show that the presence of 2.5% oxygen vacancy has no measurable effect on the elastic bulk modulus. The shear modulus, however, decreases by approximately 5% in BaCe0.85Y0.15O2.925 perovskite. The differences between Y3+ doped cerate and Al3+ doped silicate suggest that the effect of oxygen vacancy on the elastic properties could be system-dependent. In BaCe1-xYxO3-0.5x perovskite, for example, the substitution of Y3+ for Ce4+ and formation of oxygen vacancies cause a decrease in the unit-cell volume, whereas an opposite trend is revealed by both experiments and theoretical calculations for the substitution of Al3+ into Mg-silicate perovskite.

This research was partially supported by COMPRES, EAR 10-43050

Applied Physics Letters (Vol. 90, 161903-1-3, 2007).

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