Superconductor with 1212 phase of Hg,Pb,Sr,Ba,Ca,Y,Cu oxide

摘要

A family of mercury-containing Sr-(Ca.Y)-Cu-O superconducting materials having a zero-resistance temperature, Tc(zero), greater than 90 K so that they can be cooled to and maintain the desired superconducting characteristics using relatively less expensive liquid nitrogen, are disclosed. The high-temperature superconductor is represented by the formula of: (Pb0.5Hg0.5)(Sr2-xBax)(Ca0.7Y0.3)Cu2O7- delta ; wherein the value of x ranges between about 0.1 and about 0.6, preferably between about 0.2 and about 0.3. These superconducting materials are prepared by first grinding and mixing in open air constituent oxide powders of PbO, HgO, SrO2, BaO2, CaO, Y2O3, and CuO. After mixing, the powder mixture is pressed under a pressure of about 5 ton/cm2 to form a pellet having a diameter of 8 mm and a thickness of 3 mm. Thereafter, the pressed pellet is wrapped with a gold foil (with a thickness of 0.05 mm), and sealed inside a quartz tube under vacuum ( DIFFERENCE 10-4 Torr). The quartz tube containing the pellet was then placed inside a high temperature oven and sintered at 970 DEG C. for 24 hours.