MECHANISM OF THE EXCHANGE COUPLING IN TRANSITION-METAL MAGNETIC MULTILAYERS

A simple analytical model is suggested in which the oscillatory exchan ge coupling between ferromagnetic layers of a transition metal separat ed by a non-magnetic metallic spacer is a consequence of the elementar y wave mechanics of electrons in the presence of spin-polarizing bound aries. Under these conditions an oscillatory spin polarization is deve loped in the spacer. The energy of the system is calculated as a funct ion of two variables: the thickness of the spacer and the angle betwee n spin polarizations of the ferromagnets. It is shown that in the abse nce of the magnetic field the energy at any thickness is minimized by either parallel or antiparallel spin polarizations of the ferromagnets .