Superconducting transition temperature of a paramagnetic material close to magnetic ordering

Abstract

An explicit expression for the superconducting transition temperature T_c in a paramagnetic material is derived, when the transition occurs just before a possible magnetic ordering. As first noted by Uspenskii, such a transition may arise from electronic mechanism itself, without the necessary role played by the usual phonon-exchange mechanism. The result is discussed in terms of some recent experimental observations on the binary alloy Y₉Co₇.