INVESTIGATION ON SYNTHESIS AND CHARACTERIZATION OF THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.8(DELTA WITH 0.2)

In the present investigation, Tl substituted Hg bearing cuprate high t emperature superconductors corresponding to Hg1-xTlxBa2Ca2Cu3O8+delta with x = 0.2, 0.4, 0.5, 0.6, 0.7 and 0.8, have been synthesized. The a s synthesized phases characterized through XRD and TEM have been found to possess Hg:1223 as the dominant structural phase. These supercondu ctors, with increasing T1 concentration have been found to pass from t he underdoped through optimally doped to the overdoped regimes. The T- c for the underdoped regime (a = 0.2) corresponds to similar to 117 K, for the overdoped regime (a: = 0.8), it is similar to 119 K. An inter esting result emanating from the present study relates to the fact tha t an optimum T-c of similar to 122 K is Obtained through oxygenation ( annealing in oxygen) of the underdoped regime, reduction (annealing in Ar + H-2) of overdoped regime, or else through optimum hole doping by suitable adjustment of substituted Tl concentration (x = 0.6).