Spin Correlations in Itinerant Electron Magnets

Universal expressions are given for the magnetic susceptibility, the average of the squared local amplitude of spin fluctuation: S L 2 ( T ) as a function of temperature and its constituent q -components, and the spatial spin correlation function above T C . Existing experimental data for some of typical ferromagnetic metals are analyzed in terms of the longitudinal and transverse stiffness constants for the spin fluctuation, S L 2 ( T C ), and an effective wave vector cut-off parameter. Possibility for the existence of strong short range order in itinerant magnets such as Fe and Ni is discussed in the light of this analysis.