Superconducting properties of Nd1+xBa2-xCu3Oy single crystals isothermally grown at various temperatures

Nd1+xBa2-xCu3Oy (Nd123ss) single crystals were isothermally grown under controlled oxygen partial pressure of 1% O-2 at various growth temperatures (T-g) from 1000 to 1020 degrees C with a fur method. The flux composition of 20 mol% NdBa2Cu3Oy (Nd 123) and 80 mol% Ba3CU5O8 (035) was employed. Nd123ss single crystals grown at T-g greater than or equal to 1010 degrees C exhibited a transition temperature T-c approximate to 95 K with transition width approximate to 1 K, the peak field (B-pk) approximate to 2-3 T and the irreversibility field (B-irr) at 77 K much higher than the experimental limit of 7 T. As the growth temperature is lowered, both the B-pk and Bi-irr were reduced, which can be explained in terms of the chemical fluctuation which can occur at lower T-g.