(ZnxCu2-x)V2O7の熱電特性と相変態

Phase stability and thermoelectric properties of a layered structure of (ZnxCu2-x)V2O7 solid solution were studied at x ≥ 0.2. X-ray diffraction measurements, compositional studies and thermal analysis clarified that the low temperature form of (ZnxCu2-x)V2O7 solid solution (monoclinic structure, C2/c) was stable at 0.2 ≤ x ≤ 2 when annealed at 823 K in air. On heating, the phase transformation occurred at 0.2 ≤ x ≤ 2 at a nearly constant temperature around 873 K, above which a high temperature form of (ZnxCu2-x)V2O7 solid solution was formed.Seebeck coefficients of the low temperature form of (ZnxCu2-x)V2O7 solid solution showed the large negative value of about −520 to −700μV/K, and the electrical resistivity increased with Zn addition. Power factor was the maximum of 1.99 × 10−7 W/m K2 at 873K for the low temperature form of the (Zn0.2Cu1.8)V2O7 solid solution.