Fano effect and hyperfine field of a non-transition impurity in ferromagnetic transition metals

A new interpretation is given to the well known systematic trend in the hyperfine field of a non-transition impurity in Ni, Co and Fe from a view point of the Fano effect, which is a manifestation of an interference between the s, p states at a given site and the d states at the surrounding sites. It is important to note that the Fano effect can also explain the remarkable enhancement of T 1 of a non-transition impurity when it is embedded in a transition metal. The impurity Knight shift in an exchange-enhanced host metal is also discussed.