Evaluation of magnetic field hysteresis and flux creep of a QMG coil magnet

This paper presents an evaluation of the magnetic hysteresis of a coil type QMG magnet for a high field application of oxide bulk high T-c superconductors (HTS). The QMG is a high J(c) bulk material, which consists of single crystalline 123 with finely dispersed 211. The bulk coil is made from a slice of Ag doped Gd based QMG by using precise machining techniques. In the present study, magnetic field profile on the QMG coil in experiment is discussed from shielding current distribution. Magnetic field hysteresis in experiments is numerically analyzed with an axisymmetric model, where the superconductive characteristic is evaluated with a critical state model. Flux creep phenomenon in rapid magnetization with rectangular applied current is also evaluated by the numerical simulation.