Superconducting properties of Nd sub(1+x)Ba sub(2-x)Cu sub(3)O sub(y) single crystals isothermally grown at various temperatures

Nd sub(1+x)Ba sub(2-x)Cu sub(3)O sub(y) (Nd123ss) single crystals were isothermally grown under controlled oxygen partial pressure of 1% O sub(2) at various growth temperatures (T sub(g)) from 1000 to 1020 degree C with a flux method. The flux composition of 20 mol% NdBa sub(2)Cu sub(3)O sub(y) (Nd123) and 80 mol% Ba sub(3)Cu sub(5)O sub(8) (035) was employed. Nd123ss single crystals grown at T sub(g) greater than or equal to 1010 degree C exhibited a transition temperature T sub(c) approximately 95 K with transition width approximately 1 K, the peak field (B sub(pk)) approximately 2-3 T and the irreversibility field (B sub(irr)) at 77 K much higher than the experimental limit of 7 T. As the growth temperature is lowered, both the B sub(pk) and B sub(irr) were reduced, which can be explained in terms of the chemical fluctuation which can occur at lower T sub(g).