EFFECTS OF OXYGEN ON THE SUPERCONDUCTING PROPERTIES OF ND1-XCU3O7-DELTA LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.4) SOLID-SOLUTION(XBA2)

We have studied the relationship between the oxygen content and superc onducting properties for a series of Nd1+xBa2-xCu3O7-delta (0 less tha n or equal to x less than or equal to 0.4) solid solution. The tempera ture variation of oxygen content was studied as a function of x by mea ns of both TG-DTA and chemical compositional analyses. The amount of o xygen absorbed during oxygen annealing was found to decrease with an i ncreasing Nd content. In the sample with x = 0, the superconductivity transition temperature T-c increased monotonically with a decrease in the annealing temperature T-a, while T-c for the samples with larger x values shelved non-monotonic T-a dependence. The T-a value required t o achieve the highest T-c was higher than that for the largest x. On t he other hand, the pinning properties improved with a decrease in T-a. (C) 1998 Elsevier Science Ltd. All rights reserved.