ANISOTROPIC CURRENT FLOW AND DEMAGNETIZATION CORRECTIONS IN THE BEAN MODEL

In the present paper corrections to the standard Bean model are considered which turn out to be essential for the analysis of magnetization measurements on single crystals of high temperature superconductors. Because of the sensitivity of the Bean model to the actual geometrical shape of the superconductor in the plane perpendicular to the field direction, appropriate equations have to be employed. This becomes even more important if anisotropic current flow, e.g. in the ac plane of YBCO single crystals, is considered. In addition, demagnetization corrections of the measured magnetization curves are introduced. An analysis of experimental results based on these extensions of the standard Bean model shows that demagnetization corrections affect the jc values in the crystal by +21% to -6% in the worst case, whereas the inclusion of anisotropic current flow leads to an enhancement of current anisotropies by at least 100%. © 1990.