G. Domarco

Procedure to induce a persistent current in superconducting cylinders or rings

A procedure to induce a persistent current in superconducting cylinders or rings was developed using a coil and a ferromagnetic core. Using the field cooling method, the current is induced from the combined effect of the coil magnetic field and the core magnetization. The proposed method was checked using four Bi-2223 samples. The main usefulness seems to be that a high persistent current can be induced using small both probe currents and coils.

A technique for separating the trapped vortex and current in superconducting rings

In this work, a technique for separating the trapped vortices and current in YBCO superconducting rings is shown. This technique consists of heating a small part of the sample, cancelling the persistent current and keeping the vortices in the sample. Such rings are obtained from top seeding melt grown YBCO samples. To generate the persistent current in the rings an inducting technique called field cooling is used. The field is applied to the ring with a closed magnetic circuit made of an iron core and a coil. For the heating of the superconducting ring, a counter-wound coil is placed around a part of the sample. A current pass through the coil and the local heating causes the current dissipation in the superconducting ring. For magnetic field profiles in YBCO superconducting rings a Hall sensor is used, that moves at constant step on the surface of the sample.