Effect of synthesis condition on superconducting transmission temperature in Tl-Ba-Ca-Cu-O system

The formation of the high-T/sub c/ superconducting phases in the Tl-Ba-Ca-Cu-O system has been investigated. Stable superconductivity up to 119 K was observed. One of the superconducting phases displays an onset temperature of 122 K. The resistance of the TlBaCaCu/sub 2/O/sub y/ sample, which is almost single-phase, starts to drop sharply above 113 K and reaches zero at 108 K. The bulk samples with different compositions in the Tl-Ba-Ca-Cu-O system were synthesized. The electrical resistivity and AC magnetic susceptibility dependence on the temperature show that the zero-resistance transition temperature in most of the samples is above 96 K.<>