Field dependence of superconducting properties of YBa2Cu3O7-delta films onHastelloy substrates

We have investigated the E-J characteristics and resistive transition of a YBa2Cu3O7-delta (YBCO) film deposited onto polycrystalline Hastelloy with a biaxially aligned yttria stabilised zirconia (YSZ) buffer layer. The field dependence of the critical current and the irreversibility line are presen ted for both cases when the field is aligned parallel and perpendicular to the ab-planes. The critical current in zero field at 77.7 K is 8 X 10(4) A/ cm(2) and has a value of 0.6 X 10(4) A/cm(2) at 6 T with the field parallel to the ab-planes. The E-J characteristics at 77.7 K for fields parallel to the c-axis display a 'glass-like' transition. The angular dependence of th e behaviour suggests that both intrinsic pinning and pinning by the twin pl anes or low angle grain boundaries play an important role. (C) 1998 Elsevie r Science B.V. All rights reserved.