Simultaneous ESR and Magnetization Measurements Characterizing theSpin-Glass State

Two ESR modes in CuMnNi spin-glass alloys are observed. Both modes are interpreted with a phenomenological theory incorporating an order parameter, remanent magnetization, and anisotropy energy. From simultaneous magnetization and ESR measurements, it has been possible to deduce the temperature and concentration dependence of the anisotropy constant, which has interesting scaling properties. The angular dependence of the field-cooled ESR and magnetization data suggest the need for another order parameter which vanishes at $T_g$.