n. tajabor

In this research, YBa2Cu3O7- (0 <  < 1) nanocrystalite superconductor was prepared by mechanochemical alloying method. We synthesized YBa2Cu3O7- via mixing the BaCO3, 2O3, CuO powders and milling in SPEX 8000 for 5h with weight ratio of ball to powder 10:1 and steel balls of 11mm diameter, followed by heating for 4h at 850 @C. The superconductor phase formation process was completed with sintering treatment under oxygen partial pressures.The superconducting transition temperature of the samples was investigated using the four-probe method. Then transition temperature of xMnO2 + (1-x) YBa2Cu3O7- compounds was studied. The superconducting transition temperature of the final samples with x = 0, 0.005, 0.01 is found to be 83 K, and for the samples with x > 0.015, the superconductivity was vanished.

Single crystals of Cd.96Zn.04Te (CZT) with 14 mm in diameter were grown by seedless modified Bridgman method. Also, crystals with the same chemical composition were grown by vapor phase inert gas-transport method (VPGT), and single crystals up to 3.5 mm in diameter were obtained. Structural studies by XRD and back reflection Laue method show that the grown crystals are single phase with high purity, which preferentially have been grown along [111] crystal axis. The energy gap of as-grown crystals is about 1.2 eV. The electrical properties measured by Van der Pauw method, show that the resistivity is in order of 104 .cm. The electrical conductivity of crystals grown by Bridman method is p-type, and for VPGT-crystals is n-type.