Dependence on Fermi surface dimensions of oscillatory exchange coupling in Co/Cu1−x

S. N. Okuno

¹

,

K. Inomata

²

Abstract

A significant change in the oscillatory exchange coupling corresponding to the contraction of the Fermi surface in the spacer layers is found in the Co/Cui-xNi^ (110) system. The oscillation period becomes longer with increasing Ni concentration: from 12 A (0% Ni) to 23 A (35% Ni). This change manifests that the long-period oscillation across Cu-Ni (110) arises from the singularity at the neck orbit of the spacer Fermi surface. The neck diameters estimated from the measured periods are in good agreement with those of bulk Cu-Ni Fermi surfaces.

Quantum Size Effects in Ultrathin Layered Magnetic Systems

“…In a further attempt to test the theoretical predictions for the periods of oscillatory coupling, several groups [57][58][59] have undertaken to modify in a controlled manner the size of the Fermi surface (and hence, the period of the coupling) by alloying the spacer noble metal (Cu) with a metal of lower valence (Ni); in both cases, the change in oscillation period due to alloying has been found in good agreement with the expected change in the Fermi surface.…”

Interlayer Exchange Coupling and Giant Magnetoresistance in Magnetic Multilayers

“…through alloying, see e.g. [33]. In general, all experiments support the FS picture so that at present the periods of the oscillatory coupling are reasonably well understood.…”

Exchange coupling between magnetic layers across non-magnetic superlattices

“…Also, it is well know that the scattering of electrons by random impurities strongly damps the oscillations. In fact, the amplitude of the coupling is found to decay exponentially with the concentration of impurities 11,12 . An alternative to an alloy is a metallic superlattice whose Fermi surface depends on the proportions and layer thicknesses of the constituent materials but where the oscillations are not damped by incoherent electronic scattering.…”