Observation of magnetic fields due to persistent currents in a ring made of a Y1Ba2Cu3O7-delta coated conductor

A ring comprising a coated conductor was fabricated. First, the two ends of a biaxially textured Ni tape were connected by means of the atomic diffusi on bonding technique. Then buffer layers and a YBCO film were deposited on the ring. All the films were well textured as confirmed by XRD pole figures . The B-H loops, where B and H are the magnetic field at the centre of the ring and the applied field, respectively, were measured as a function of te mperature. The persistent current density (J(c)) flowing circularly was est imated from the remanent field of B. In the range of temperatures from 72 t o 20 K, J(c) changed from 0 to 2 x 10(5) A cm(-2).