Spin polarization of a magnetic electron gas induced by a van Vleck ion

The mutual polarization of a magnetic electron gas and a van Vleck ion, interacting via exchange, are theoretically investigated using the double‐time Green function method. A pair of equations describing the dynamics of the electron gas and the ion are conveniently decoupled and an analytic expression for the electron gas polarization is obtained which depends on the square of the exchange parameter. Besides a RKKY‐like term, a new term associated to the process of formation of the magnetic moment of the ion appears.