Spin-polarized quantum well states

Altmann, K. N.; O’Brien, W. L.; Seo, Dong Ju; Himpsel, F. J.; Ortega, J. E.; Naermann, A; Segovia, P.; Mascaraque, A.; Michel, E. G.

doi:10.1016/s0368-2048(98)00389-2

Cited by 6 publications

(5 citation statements)

References 14 publications

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“…figure 9). By contrast, all the published results on the fcc Co(100)/Cu, system, which has been studied extensively by several groups [49,[65][66][67][68][69][70], seem to indicate relatively rough and inhomogeneous films. We have already remarked on this in relation to the apparent continuous evolution of QW state energies with film thickness in figure 8.…”

Section: Photon Energy Dependence Of Quantum Well Photoemissionmentioning

confidence: 92%

Quantum well structures in thin metal films: simple model physics in reality?

2002

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The quantum wells formed by ultra-thin metallic films on appropriate metallic substrates provide a real example of the simple undergraduate physics problem in quantum mechanics of the 'particle in a box'. Photoemission provides a direct probe of the energy of the resulting quantized bound states. In this review the relationship of this simple model system to the real metallic quantum well (QW) is explored, including the way that the exact nature of the boundaries can be taken into account in a relative simple way through the 'phase accumulation model'. More detailed aspects of the photoemission probe of QW states are also discussed, notably of the physical processes governing the photon energy dependence of the cross sections, of the influence of temperature, and the processes governing the observed peak widths. These aspects are illustrated with the results of experiments and theoretical studies, especially for the model systems Ag on Fe(100), Ag on V(100) and Cu on fcc Co(100).

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Section: Photon Energy Dependence Of Quantum Well Photoemissionmentioning

confidence: 92%

Quantum well structures in thin metal films: simple model physics in reality?

2002

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“…The role of quantum well states was demonstrated by Weber et al [1225] in Cu/Co/Cu(0 0 1) (using slightly miscut Cu single crystals) who observed a periodic oscillation in the magnetic anisotropy as a function of the Cu capping layer, see figure 27. Changes in the band structure from quantum well states [92][93][94][95][96][97][98][99][102][103][104] modify the magnetic anisotropy via spin-orbit coupling, but with a characteristic oscillation period that need not coincide with that observed for interlayer coupling [1048,[1239][1240][1241][1242][1243][1244][1245] since the electronic states affecting the magnetic anisotropy issue from the entire Brillouin zone, unlike the exchange coupling which is governed by states at the Fermi surface [1225]. The observed period of the oscillation (3-4 ML) is independent of the Co film thickness, and for a 10.8 ML Co film, the anisotropy easy axis is found to oscillate between the [1 1 0] and [1 1 0] directions, as shown in figure 27.…”

Section: Fcc Co/cu(0 0 1)mentioning

confidence: 99%

“…Originally, this effect was identified in structures with fixed Cr thickness, for which an antiparallel alignment of the Fe layers is favoured due to the interlayer exchange coupling across the Cr spacer layer. The coupling strength was since found [90,91] to oscillate with thickness in a wide range of spacer materials (so-called oscillatory coupling) and this behaviour has since been theoretically described in terms of RKKY interactions in the 2D geometry and magnetic quantum well effects within the spacer layer [92][93][94][95][96][97][98][99][100][101][102][103][104]. New applications based on these discoveries have fuelled much excitement in this field as well as creating new important technologies.…”

Section: An Introduction To the Physics Of Magnetism In Ultrathin Filmsmentioning

confidence: 99%

Magnetism in ultrathin film structures

Vaz¹,

Bland²,

2008

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In this paper, we review some of the key concepts in ultrathin film magnetism which underpin nanomagnetism. We survey the results of recent experimental and theoretical studies of well characterized epitaxial structures based on Fe, Co and Ni to illustrate how intrinsic fundamental properties such as the magnetic exchange interactions, magnetic moment and magnetic anisotropies change markedly in ultrathin films as compared with their bulk counterparts, and to emphasize the role of atomic scale structure, strain and crystallinity in determining the magnetic properties. After introducing the key length scales in magnetism, we describe the 2D magnetic phase transition and survey studies of the thickness dependent Curie temperature and the critical exponents which characterize the paramagnetic-ferromagnetic phase transition. We next discuss recent experimental and theoretical results on the determination of the exchange constant, followed by an overview of measurements of the magnetic moment in the elemental 3d transition metal thin films in the various crystal phases that have been successfully stabilized, thereby illustrating the sensitivity of the magnetic moment to the local symmetry and to the atomic environment. Finally, we discuss briefly the magnetic anisotropies of Fe, Co and Ni in the fcc crystalline phase, to emphasize the role of structure and the details of the interface in influencing the magnetic properties. The dramatic effect that adsorbates can have on the magnetic anisotropies of thin magnetic films is also discussed. Our survey demonstrates that the fundamental properties, namely, the magnetic moment and magnetic anisotropies of ultrathin films have dramatically different behaviour compared with those of the bulk while the comparable size of the structural and magnetic contributions to the total energy of ultrathin structures results in an exquisitely sensitive dependence of the magnetic properties on the film structure.

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“…Moreover, since electric field screening involves redistribution of the surface charge, it should obviously affect the boundary conditions of the QWSs, if the latter exist in the system. In particular, spin-polarized QWSs [130] are conceivably a good candidate for acting as a mediator between the electric field and magnetic properties of the system. As a particular example, it has been demonstrated that in magnetic tunneling junctions involving Fe thin films the contribution from the QWSs to the resonant tunneling through the iron films is significant [131].…”

Section: Tuning Magnetic Properties Of Thin Films With External Elect...mentioning

confidence: 99%

Controlling magnetism on metal surfaces with non-magnetic means: electric fields and surface charging

Brovko

Ruiz-Díaz

Dasa

et al. 2014

J. Phys.: Condens. Matter

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We review the state of the art of surface magnetic property control with non-magnetic means, concentrating on metallic surfaces and techniques such as charge-doping or external electric field (EEF) application. Magneto-electric coupling via EEF-based charge manipulation is discussed as a way to tailor single adatom spins, exchange interaction between adsorbates or anisotropies of layered systems. The mechanisms of paramagnetic and spin-dependent electric field screening and the effect thereof on surface magnetism are discussed in the framework of theoretical and experimental studies. The possibility to enhance the effect of EEF by immersing the target system into an electrolyte or ionic liquid is discussed by the example of substitutional impurities and metallic alloy multilayers. A similar physics is pointed out for the case of charge traps, metallic systems decoupled from a bulk electron bath. In that case the charging provides the charge carrier density changes necessary to affect the magnetic moments and anisotropies in the system. Finally, the option of using quasi-free electrons rather than localized atomic spins for surface magnetism control is discussed with the example of Shockley-type metallic surface states confined to magnetic nanoislands.

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Spin-polarized quantum well states

Cited by 6 publications

References 14 publications

Quantum well structures in thin metal films: simple model physics in reality?

Quantum well structures in thin metal films: simple model physics in reality?

Magnetism in ultrathin film structures

Controlling magnetism on metal surfaces with non-magnetic means: electric fields and surface charging

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