The Paramagnetic Mixed State

Abstract

It will be recalled that (13–57) and its predecessor (13–44) relied on the validity of replacing g _n (H _c ) with g _n (H _a ) (cf. (13–43) and (13–44)). Obviously if g is field-dependent to an extent beyond that already implied in the derivations of these relationships, as it is when the normal-state and mixed-state paramagnetisms must be taken into consideration, the original energy- balance is upset and the equilibrium has to be reevaluated. The goals of the various paramagnetic theories of the mixed state have been to take into account the effects of these additional paramagnetic energy terms while developing expressions for the temperature dependence of the upper critical field (now reduced from H*_c2 to H _c2 through the intervention of a paramagnetically limited upper critical field, H _p ), and, peripherally, to provide guidance to the designers of high-H_c2 superconductors.