Critical state modelling of crossed field demagnetisation in HTS materials

Large magnetic fields can be trapped in high temperature superconductor material,
enabling their use as permanent magnets in various applications. It has, however, been
observed that these materials experience a decay in magnetisation when a field is applied
in a direction transverse to the trapped field. This paper presents the results of critical state
modelling of an infinite slab of superconductor that is first fully magnetised and then exposed
to magnetic field in the transverse direction. The bean and double critical state model are
implemented and the results compared to each other and to that of physical experiment. The
convergence of the decay is investigated as well as the effect of the magnitude of the crossed
field on the final decay value. Diamagnetic and paramagnetic initial conditions are applied to
the material and the results used to compare the accuracy of the bean and double critical state
model.