%0 Journal Article %T The syntesis of YBa2Cu3O7- nanocrystalites via mechanochemical alloying  study transition temperature of xMnO2 + (1-x) YBa2Cu3O7- compounds %J Iranian Journal of Crystallography and Mineralogy %V 19 %N 2 %U http://ijcm.ir/article-1-443-en.html %R %D 2011 %K Superconductivity, YBa2Cu3O7-, Mechanochemical, MnO2, Transition Temperature., %X In this research, YBa2Cu3O7-d (0 < d < 1) nanocrystalite superconductor was prepared by mechanochemical alloying method. We synthesized YBa2Cu3O7-d via mixing the BaCO3, Y2O3, 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-d 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.ر %> http://ijcm.ir/article-1-443-en.pdf %P 219-226 %& 219 %! %9 Research %L A-10-134-132 %+ %G eng %@ 1726-3689 %[ 2011