Limitations of the London model for the reversible magnetization of type-II superconductors

We point out that the London model for the reversible magnetization M of high-{κ} type-II superconductors in the intermediate-field region is quantitatively incorrect, and we discuss the implications on our understanding of the mixed state of type-II superconductors. We also show that the apparently linear dependence of M vs lnH in the intermediate-field region, a behavior that has been observed experimentally, can be obtained from a previously proposed variational model.