Determination of Hole Concentration and Characteristic Pseudogap Temperature in Underdoped and Overdoped YBa2Cu3O7-δ System.

Electrical resistivity measurements in the temperature range 14 - 300K have been carried out on superconducting materials of the composition, Y0.9-xPrxCa0.1Ba2[Cu1-yZny]3O7-δ. with different values of x and y (0 ≤ x ≤ 0.2 and (0 ≤ y ≤ 0.06). In order to study the underdoped region Ca content is reduced to zero and Pr content is changed from x = 0.1 to 0.2. for varying contents Zn . For the overdoped region Ca = 0.1 and x is varied from 0 to 0.2 for two values of Zn content 0.02 and 0.06. From the analysis of the electrical resistivity data obtained for the above cuprates the characteristic pseudogap temperatures and the exponent, m, in fits to m ρ (T) = ρo + aTm have been found out. The planar hole concentration, p has been determined by the room temperature measurements of thermoelectric power . Using these results a doping phase diagram has been constructed for these superconducting materials. [ABSTRACT FROM AUTHOR]