CuTa2O6: crystal growth and characterization

The compound CuTa2O6 has been prepared as crystals from a Cu/O melt and found to be tetragonal (a = 7.510 A, c = 7.526 A) rather than cubic as reported in the literature. The coefficient of thermal expansion between room temperature and 10000C was found to be 8.0 x 10-60C-1. Electrical resistivity measurements on a crystal showed semiconductor behavior between room temperature (rho = 2 x 103 Ωcm) and 1400K (rho = 7 x 106 Ωcm) with an activation energy of E/sub A/ = 0.2 eV. Magnetic measurements between 4.20K and room temperature showed Curie--Weiss behavior with a change in μeff at 1200K+ For T greater than 1200K, μeff = 1.76 μ/sub B/ and theta/sub p/ = 00K while for T less than 1200K μeff = 1.91 μ/sub B/ and theta/sub p/ = -150K