Interlayer magnetic coupling: Effect of alloying in the spacer

The influence of alloying in the spacer on the periods and the amplitudes of the oscillations of exchange coupling in magnetic multilayers is studied from first principles. The effect of substitutional randomness in the spacer is treated within the coherent potential approximation and the validity of the simplified virtual-crystal approximation is examined. As a case study, results obtained for Co(001) slabs in random fcc ${\mathrm{Cu}}_{1-x}{M}_x$ spacers ($M=\mathrm{N}\mathrm{i},\mathrm{Z}\mathrm{n},\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{A}\mathrm{u}$) are presented and discussed.