Anisotropic Thermal Diffusivity and Conductivity of La-Doped Strontium Niobate Sr2Nb2O7
Abstract:The thermal diffusivity of the La-doped layered perovskite Sr2Nb2O7 parallel and perpendicular to the perovskite layers is reported from room temperature up to 1000°C. The anisotropy persists through an incommensurate-normal ferroelectric phase transformation at 215°C and up to 1000°C, the maximum temperature of our measurements. The thermal conductivity perpendicular to the perovskite layers, derived from the diffusivity in the same direction, calculated using the density and measured heat capacity, has a constant value of 1.05±0.05 W/mK up to 1000°C. Possible explanations for the low thermal conductivity and anisotropy are described.
Document Type: Research Article
Affiliations: 1: Materials Department, College of Engineering, University of California, Santa Barbara, California 93106-5050 2: Department of Materials and Metallurgical Engineering, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 3: School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
Publication date: April 1, 2010