Apparent spin-glass nature of an anisotropic ferromagnet

Low-field ac and dc magnetization measurements on a Pd-0.4 at. %Fe sample in two metallurgical states are presented. In a well-annealed state the sample responds like an ideal soft ferromagnet. After plastic deformation the sample has essentially the same ordering temperature and saturation magnetization, however, its low-field response looks more like that of a spin glass. Magnetic isotherms in this latter state look like those of a ferromagnet with infinite susceptibility but zero spontaneous magnetization.