Preparation of Y-Ba-Cu-O Superconductors with High Critical Current Density by Unidirectional Melt Solidification

Y-Ba-Cu-O superconductors with high J c have been prepared by a unidirectional melt solidification method. Uniformly oriented plate-shaped YBa 2 Cu 3 O 7- y crystals containing small particles of Y 2 BaCuO 5 have been grown successfully using the material with the nominal composition of Y 1+ x Ba 2- x Cu 3-2 x O z ( x ≦0.4) as a starting material. The J c values of the unidirectionally solidified Y-Ba-Cu-O samples, measured at 77 K using a four-probe method with continuous direct current, were 4600 and 12000 A/cm 2 in 1 and 0.25 T, respectively. These values nearly coincided with those estimated from magnetization hysteresis loops using Bean's critical state model.