Physics and Astronomy Faculty Publications

Document Type

Article

Abstract

A large single crystal of barium tungstate BaWO4 with dimensions of 22- mm diameter 80-mm length was grown by the Czochralski method using an iridium crucible. The melting point, molar enthalpy of fusion, and molar entropy of fusion of the crystal were determined to be 1775.10 K, 96 913.80 J mol−1, and 54.60 J K−1 mol−1, respectively. The average linear thermal-expansion coefficients are a=10.9526 10−6/K, b=10.8069 10−6 /K, and c =35.1063 10−6 /K in the temperature range from 303.15 to 1423.15 K along the three respective crystallographic axes. The density of the crystal follows an almost linear decrease from 6.393 103 to 6.000 103 kg m−3 when the temperature is increased from 303.15 to 1423.15 K. The measured specific heat are 115.56–130.96 J K−1 mol−1 in the temperature range of 323.15–1173.15 K. The thermal diffusion coefficient of the crystal was measured in the temperature range of 297.15–563.15 K. The calculated thermal conductivity is 2.256 W m−1 K−1 along the 001 direction and 2.324 W m−1 K−1 along the 100 direction at 323.15 K. The microhardness of the BaWO4 single crystal in the 001 and 100 planes is 1393 and 1814 MPa under a load of 0.050 kg.

Publication Date

2005

Publication Title

Journal of Applied Physics

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