Magnetization of the Superconducting Sheath

Torque measurements on Type-II superconducting foils in nearly parallel applied magnetic fields $H$ indicate that the torque above $H_{c2\mathrm{}}$ can provide a direct measure of the magnetization. From the results above $H_{c2\mathrm{}}$ we deduce two magnetizations, $M_b$ associated with the bulk sample, and $M_s$ associated only with the superconducting sheath. The measurements indicate that $M_s$ is irreversible with $H$, contrary to prediction, and that the sheath itself behaves as if it is multiply connected.