Temperature dependent total scattering structural study of CaCu3Ti4O12

Abstract

X-ray and neutron powder diffraction data as a function of temperature are analyzed for the colossal dielectric constant material CaCu3Ti4O12. The local structure is studied using atomic pair distribution function analysis. No evidence is found for enhanced oxygen displacement parameters suggesting that short-range octahedral tilt disorder is minimal. However, an unusual temperature dependence for the atomic displacement parameters of calcium and copper is observed. Temperature dependent modeling of the structure, using bond valence concepts, suggests that the calcium atoms become underbonded below approximately 260 K, which provides a rationale for the unusually high Ca displacement parameters at low temperature.

9 pages, 7 figures

References in corpus (6)

• Materials with Colossal Dielectric Constant: Do They Exist?
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Cited by in corpus (1)

• Defect Structure of the High-Dielectric-Constant Perovskite Cacu3ti4o12