CRITICAL CURRENTS OF YBA2CU3OY THICK-FILMS PREPARED BY LIQUID-PHASE EPITAXIAL-GROWTH

We have succeeded in preparing c-axis oriented high-J(c) YBa2Cu3Oy fil ms on MgO(100) substrate by the liquid phase epitaxy (LPE) technique. The growth rate was typically about 2 mu m/min, which was 10-10(2) tim es larger than that by ordinary vapor growth techniques. The film thic kness ranged 10-50 mu m by choosing the dipping time. The T-c of the b est film exceeded 88 Ii after oxygen annealing, and the transport J(c) was 1.1X10(5) A/cm(2) at 77 K and 0 T In-field J(c) 's at 77 K and 1. 5 T were 2.8X10(4) A/cm(2) and 2.0X10(4) A/cm(2) for the B perpendicul ar to ab plane and B parallel to ab plane, respectively. In addition, the peak effect of J(c) was observed at several tesla for B parallel t o ab plane geometry. Based on the microstructure observed by high reso lution transmission electron microscopy, the relevant peak effect is c onsidered to be caused by stacking faults which act as a field induced pinning center.