Aspects of magnetic disorder

A brief review is given of the effects that quenched, magnetic disorder have on the magnetic properties of systems with short-range interactions. Of primary interest are random exchange, random anisotropy and random fields. Recent theoretical and experimental studies have begun to illuminate the unusual critical behavior that is seen in randomly diluted antiferromagnets in the presence of a uniform field, which is the most direct manner by which the random field problem may be approached. Considerable uncertainty still exists as to what is the lower critical dimensionalityd₁ and the effective dimensionality ¯d ford-dimension Ising systems in the presence of a random field. This whole area appears to be one in which further insight might be gained through the application of microscopic probes such as NMR, Mössbauer Effect andSR.