The Origins and Influences of the Spin-Glass Problem

Abstract

In recent years there has been a burst of interest in what is called the spin-glass problem. This concerns the nature of the magnetic state of systems containing a distribution of magnetic-moment-carrying atoms distributed with some degree of randomness (generally on a small fraction of the atomic sites of a metal crystal, the other site being occupied by non-magnetic atoms), such that there exist both parallel and antiparallel couplings between moments. The ground state clearly lacks long-range magnetic order, but the nature of that state and of the transition to it from the high temperature paramagnetic state is still not clear. This topic is of interest not only as a scientific problem, but also as a good example of the way in which new sub-fields of study in solid state physics emerge and it is as such an example that it is considered here. A rather more complex story could be constructed for the dilute alloy (Kondo) problem, where the interactions between moments can be ignored.