Quantum-Well Contributions to the RKKY Coupling in Magnetic Multilayers

Abstract

We study the effects of quantum-well states on the calculated RKKY coupling. We find that the bound states of a finite-size potential well of depth V give an added oscillation period of size \(\pi \hbar /\sqrt {2mV} \). For the simplest case of a spherical free-electron Fermi surface, thus two periods appear: the original, “fast,” π/kF oscillation, and the quantum-well one \(\pi \hbar /\sqrt {2mV} \). The quantum-well contributions have larger amplitude, and are in fact the predominant oscillation. For physically reasonable V (tenths of an eV) this period is around 8–10Å. We discuss evidence for these effects in experimental systems.

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Acknoledgments

We acknowledge helpful discussions with S. Parkin, F. Herman, J. R. Schrieffer, J. Slonczewski, M. Stiles, and V. Kalmeyer. This research was supported in part by the Aspen Center for Physics, and by the National Science Foundation under Grant No. PHY89-04035.

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Correspondence to B. A. Jones.

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Jones, B.A., Hanna, C.Β. Quantum-Well Contributions to the RKKY Coupling in Magnetic Multilayers. MRS Online Proceedings Library 313, 165–169 (1993). https://doi.org/10.1557/PROC-313-165

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