SUPERCONDUCTORS OF FINITE THICKNESS IN A PERPENDICULAR MAGNETIC-FIELD- STRIPS AND SLABS

The magnetic moment, flux and current penetration, and creep in type-I I superconductors of nonzero thickness in a perpendicular applied magn etic field are calculated. The presented method extends previous one-d imensional theories of thin strips and disks to the more realistic cas e of arbitrary thickness, including as limits the perpendicular geomet ry (thin long strips and circular disks in a perpendicular field) and the parallel geometry (long slabs and cylinders in a parallel field). The method applies to arbitrary cross section and arbitrary current-vo ltage characteristics E(J) of conductors and superconductors, but a li near equilibrium magnetization curve B = mu(0)H and isotropy are assum ed. Detailed results are given for rectangular cross sections 2a x 2b and power-law electric field E(J) = E(c)(J/J(c))(n) versus current den sity J, which includes the Ohmic (n = 1) and Bean(n-->infinity) limits . In the Bean limit above some applied field value the lens-shaped flu x- and current-free core disconnects from the surface, in contrast to previous estimates based on the thin strip solution. The ideal diamagn etic moment, the saturation moment, the field of full penetration, and the complete magnetization curves are given for all side ratios 0 < b /a < infinity.