Theory of interlayer magnetic coupling

Abstract

A theory of interlayer exchange coupling is presented. A detailed and comprehensive discussion of the various aspects of the problem is given. The interlayer exchange coupling is described in terms of quantum interferences due to confinement in ultrathin layers. This approach provides both a physically transparent picture of the coupling mechanism, and a suitable scheme for discussing the case of a realistic system. This is illustrated for the Co/Cu/Co(OOI) system. The cases of metallic and insulating spacers are treated in a unified manner by introducing the concept of the complex Fermi surface.

Superconducting and normal-state interlayer exchange coupling inLa0.67Sr0.33MnO3−YSenapati1, Budhani2 2005Phys. Rev. B360350View full textAdd to dashboardCite

“…The characteristic decay length λ inferred from the fit is ∼ 150Å. Since the c-axis transport in YBCO is controlled by a delicate balance between single electron tunneling and intralayer electron -electron scattering processes 46,47,48 , a tunneling picture for IEC is applicable, albeit with the caveat that it is unlike the tunneling through a semiconducting barrier where thermally induced carriers can enhance IEC at higher temperatures 44 . The IEC in this case is expected to decay with temperature as the c-axis resistivity shows a linear temperature dependence.…”

“…9 as a function of the spacer layer thickness. We have fitted these data to a first-order exponential decay of the type given by Bruno et al 44 . Result of this fitting is shown as solid-lines in the inset.…”

“…Below this temperature a truncation of the monotonic growth of J 1 is evident in all samples. The temperature dependence of the interlayer exchange coupling in metallic multilayers has been worked out theoretically 43,44 . Following Bruno 44 , the amplitude of the linear exchange coupling coefficient J 1 increases with the decreasing temperature in the following manner,…”

Semiconductor Ferromagnetic Structures

“…Since then, it proved to be a rich field of fundamental research in modern magnetism and played key roles in many technological applications. So far, the vast scientific activity in this field has been focused on metallic systems in which the interlayer coupling can be explained in terms of quantum interference of electron waves of quasi-free conducting carriers in spin dependent potential of magnetic multilayer or, equivalently, via the spin polarization of conducting carriers (an analog of the RKKY interaction [2,3]). The necessary condition for the RKKY mechanism to play a significant role is the presence of a high concentration of carriers in the multilayer.…”

“…Recently, the impressive progress has been achieved in the field of low dimensional layered magnetic structures composed of ferromagnetic and nonmagnetic metals such as, e.g., Co-Cu multilayers [1][2][3]. The discovery of a variety of new effects such as, e.g., interlayer exchange coupling or giant magnetoresistance, has led to successful applications in magnetoresistive and magnetooptical sensors [4,5].…”