The Stoner glass

A theory of spin-glass condensation in a disordered itinerant-electron system without well-developed local moments is presented. The theory applies to finite-concentration impurity systems at temperatures well below their Kondo temperatures; such as $\mathrm{Rh}\mathrm{Co}$. The local spin fluctuations at impurity sites are coupled to each other via the magnetic response of the host-metal electrons, and since this interaction is effectively random, a phase transition to a frozen state characterized by an Edwards-Anderson spin-glass order parameter can occur. A mean-field description of this transition and state is given here, paying particular attention to the requirement of mutually consistent approximations for the susceptibility, order parameter, and order-parameter susceptibility. An interesting formal aspect of the theory is the fact that fluctuation corrections to the susceptibility, of the sort which occurs in the Moriya-Kawabata and Hertz-Klenin theory of itinerant ferromagnets, are necessary for a consistent description of the spin-glass case.