Effects of oxygen content on the superconducting properties of melt-textured LRE123 superconductors

The effects of oxygen content on the superconducting transition temperatures, T-c, and magnetic properties of melt-textured LRE123 (LRE = Nd, Sm) superconductors were studied. The oxygen content could be varied by changing the annealing temperature, T-a, in that the oxygen deficiency, delta, monotonically decreased with decreasing the T-a from 600 degrees C to 300 degrees C. A further decrease of T-c to 275 degrees C showed no appreciable change. In both systems the highest T-c was obtained for the samples annealed at 300 degrees C. Magnetic properties were also strongly dependent on the oxygen content, showing that the control of oxygen content is critical for achieving good pinning properties. (C) 1997 Elsevier Science B.V.