Magnetic States of Single Impurity and Impurity Pair in Ferromagnetic Metals

The magnetic state of a single impurity and an impurity pair in ferromagnetic metals are discussed on the basis of the tight binding model by bearing in mind transition metals. The most stable state of the single impurity obtained as the solution of the Hartree Fock approximation for the intraatomic interaction in the impurity atom is shown to be that with a magnetic moment either parallel or antiparallel to the bulk magnetization. In the case of the impurity pair, a similar calculation shows that the state with canted magnetic moments with respect to each other and also to the magnetization as well as those with parallel and antiparallel moments can be the most stable one. In the light of these calculations, the speculative discussions about the possibility of the existence of a ferromagnetic concentrated alloy with a finite fraction of canted atomic magnetic moments are given.