Annealing (metallurgy) brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further work—such as shaping, stamping, or forming. Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state. Heat increases the rate of diffusion by providing the energy needed to break bonds. The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics. This
Spin glass as the sample is cooled to the transition temperature, magnetization of the sample increases as described by the Curie law. Upon reaching "T", the sample becomes a spin glass and further cooling results in little change in magnetization. This is referred to as the "field-cooled" magnetization. When the external magnetic field is removed, the magnetization of the spin glass falls rapidly to a lower value known as the "remanent" magnetization. Magnetization then decays slowly as it approaches zero (or some small fraction of the original value—this remains unknown). This decay is non-exponential and no simple function can fit the curve