PRODUCTION OF OXIDE SUPERCONDUCTOR SINGLE CRYSTAL AND METHOD FOR CONTROLLING SUPERCONDUCTIVITY TRANSITION TEMPERATURE

摘要

PURPOSE:To produce the Tl2 Ba2CuO6 single crystal having good quality and suffucient size by heating and melting a powder mixture composed of Tl2O3, BaO, CuO, KCl, and NaCl consisting of specific compounding ratios under specific conditions, then slowly cooling the mixture. CONSTITUTION:The powder mixture of the compsn. range consisting of Tl2O3+2 BaO+CuO+x{(1-y)KCl+nNaCl}3=x=500, 0=y=1) is melted by using KCl and/or NaCl as a flux at 700 to 900 deg.C temp. range and the melt is slowly cooled at a rate of =10 deg.C/hour. The resulted single crystal is washed with water to remove KCl and NaCl. The single crystal of the Tl2Ba2CuO6 is taken out. The single crystal of the Tl2Ba2CuO6 having the good quality and the sufficient size is obtd. in this way and is subjected to the heat treatment in the temp. range of 300 to 600 deg.C under the pressurized oxygen up to 400atm, by which the superconductivity transition temp. (Tc) is arbitrarily controlled in an about 0 to 85K range.