First-Order Transitions at Hc1 and Hc2 in Type II Superconductors

It is predicted that, for type-II superconductors with κ values near 12 at temperatures below T_c, the transition at H_c1 is first order when ξ₀l<~50 and the transition at H_c2 is first order when ξ₀l>~50. It may not be possible to observe the latter transition because of experimental difficulties but the former transition should be observable. We also show that the vanishing of the normal-superconducting wall energy is irrelevant for determining if a given superconductor is type I or type II.