Exchange coupling of magnetic multilayers in spin-polarized jellium

The bilinear and biquadratic coupling between two metallic layers separated by nonmagnetic metal spacer are studied. The paper contains analytical formulae for the coupling which are obtained from the energy potential of the spin-polarized electron gas. The formulae for the coupling are obtained in the framework of the Hohenberg-Kohn formalism of the density functional theory and variables of the coupling are the electron density and spin polarization of the magnetic multilayer. (author)