Quantum-well-induced ferromagnetism in thin films

Niklasson, Anders M. N.; Mirbt, Susanne; Skriver, Hans Lomholt; Johansson, Börje

doi:10.1103/physrevb.56.3276

Cited by 44 publications

(46 citation statements)

References 25 publications

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“…We use this technique to probe two Sc-C 60 and Cu-C 60 samples whose structure includes a thin Sc film of 2 nm (2.5 nm for Cu-C 60 ) and a thick Sc film of 5 nm (15 nm for Cu-C 60 ). Nanoscaling of nonmagnetic metals has been shown to give rise to spin ordering (30)(31)(32)(33). The thin films should give rise to a strong magnetic signal, whereas for the thicker films, the interfacial magnetization should be quenched or diluted by the bulk properties of the metal.…”

Section: Systemmentioning

confidence: 99%

Emergent magnetism at transition-metal–nanocarbon interfaces

Ma’Mari

Rogers

Alghamdi

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Charge transfer at metallo-molecular interfaces may be used to design multifunctional hybrids with an emergent magnetization that may offer an eco-friendly and tunable alternative to conventional magnets and devices. Here, we investigate the origin of the magnetism arising at these interfaces by using different techniques to probe 3d and 5d metal films such as Sc, Mn, Cu, and Pt in contact with fullerenes and rf-sputtered carbon layers. These systems exhibit small anisotropy and coercivity together with a high Curie point. Low-energy muon spin spectroscopy in Cu and Sc-C 60 multilayers show a quick spin depolarization and oscillations attributed to nonuniform local magnetic fields close to the metallo-carbon interface. The hybridization state of the carbon layers plays a crucial role, and we observe an increased magnetization as sp 3 orbitals are annealed into sp 2 −π graphitic states in sputtered carbon/copper multilayers. X-ray magnetic circular dichroism (XMCD) measurements at the carbon K edge of C 60 layers in contact with Sc films show spin polarization in the lowest unoccupied molecular orbital (LUMO) and higher π*-molecular levels, whereas the dichroism in the σ*-resonances is small or nonexistent. These results support the idea of an interaction mediated via charge transfer from the metal and dz-π hybridization. Thin-film carbon-based magnets may allow for the manipulation of spin ordering at metallic surfaces using electrooptical signals, with potential applications in computing, sensors, and other multifunctional magnetic devices. emergent magnetism | molecular spintronics | interfacial magnetism | charge transfer | nanocarbon I nterfaces are critical in quantum physics, and therefore we must explore the potential for designer hybrid materials that profit from promising combinatory effects. In particular, the fine-tuning of spin polarization at metallo-organic interfaces opens a realm of possibilities, from the direct applications in molecular spintronics and thin-film magnetism to biomedical imaging or quantum computing. This interaction at the surface can control the spin polarization in magnetic field sensors, generate magnetization spin-filtering effects in nonmagnetic electrodes, or even give rise to a spontaneous spin ordering in nonmagnetic elements such as diamagnetic copper and paramagnetic manganese (1-11).The impact of carbon-based molecules on adjacent ferromagnets is not limited to spin filtering and electronic transport, but extends to induced changes in the metal anisotropy, magnetization, coercivity, and bias (12-14). Charge transfer and d(metal)-π(carbon) orbital coupling at the interface may change the density of states, spin population, and exchange of metallocarbon interfaces (4,15,16). The interaction between the molecule and the metal depends strongly on the morphology and specific molecular geometry (17, 18). It may lead to a change in the density of states at the Fermi energy DOS(E F ) and/or the exchange-correlation integral (I s ) as described by the Stoner criterion for ferr...

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Section: Systemmentioning

confidence: 99%

Emergent magnetism at transition-metal–nanocarbon interfaces

Ma’Mari

Rogers

Alghamdi

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Here, most of the systems examined have been Rh adlayers on noble metal substrates. Theoretical predictions have suggested that single Rh MLs will be magnetic on Ag (111) [16,17] and (001) [13,16,[18][19][20][21][22][23][24], Au (111) [16] and (001) [13,16,23,25], Ni (111) [26] and Cu (001) [16,[27][28][29] but non-magnetic on Ag (110) [16], Au (110) [16], Cu (110) [16] and Cu (111) [16]. In the magnetic cases, the moments are predicted to decrease rapidly with increasing numbers of Rh layers, usually becoming very weak by film thicknesses of just 2 ML [26,30].…”

Section: Introductionmentioning

confidence: 99%

Correlations between magnetic properties and bond formation in Rh–MgO(0 0 1)

Castleton¹,

Nokbin²,

Hermansson³

2007

Surface Science

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We present the results of first principles calculations for the magnetism of Rh adlayers on MgO (001), at three different adsorption sites and three different coverages, corresponding to 1, 1/2 and 1/8 monolayers. Finite magnetization is found in all cases except that of 1 Rh monolayer above the oxygen site, which is also the most stable. We examine how the magnetization changes as a function of the Rh-surface distance and relate this to changes in the real space charge density and in the density of states (DOS) as the Rh adlayer interacts with the surface.We find that increasing either the Rh-Rh interaction strength or the Rh-surface interaction strength leads to reduced magnetization, while increasing the former drives a crossover from localized (atomic) to itinerant magnetism. Neither the magnetic transition itself, nor the localized-to-itinerant magnetism crossover, is found to be directly related to the formation of Rhsurface bonds. From a practical point of view, we predict that magnetism in the Rh-MgO (001) system is most likely to be found experimentally at reduced coverages and at low temperatures. Manuscript

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“…The discussion is close to previous work 35 where it was shown how multiple-scattering effects such as quantum-well states only give a small, almost constant, contribution to the magnetic profile in Fe/Cu/Fe trilayers. Multiple-scattering effects can sometimes be important for the magnetization in thin films and may even induce an onset of magnetism in paramagnetic materials 36 or quench the magnetism in ferromagnetic materials. 37 However, these enhancements or quenching effects are mainly of importance for thin films of nearly magnetic materials such as Rh, Pd, and Pt.…”

Section: Magnetic Trilayersmentioning

confidence: 99%

Interface magnetism of3dtransition metals

1999

Self Cite

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The layered resolved magnetic spin moments of the magnetic 3d bilayer interfaces Fe/V bcc, Fe/Co bcc, Fe/Cu bcc, Co/V bcc, Co/Ni fcc, Co/Cu fcc, Ni/V fcc, Ni/Cr fcc, Ni/Cu fcc and the magnetic surfaces Fe bcc, Co bcc, Co fcc, and Ni fcc are calculated for the ͑001͒, ͑011͒, and ͑111͒ orientations by means of a firstprinciples Green's function method. It is shown how the magnetic profiles around the bilayer interfaces and surfaces directly can be used to predict the magnetization of more complex systems such as magnetic multilayers and clusters. Furthermore, it is shown how the magnetic interface moments can be estimated from data of the corresponding binary bulk alloys. The behavior of interface magnetism can thus be traced back to the understanding of magnetism in bulk alloys. ͓S0163-1829͑99͒04005-9͔

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Quantum-well-induced ferromagnetism in thin films

Cited by 44 publications

References 25 publications

Emergent magnetism at transition-metal–nanocarbon interfaces

Emergent magnetism at transition-metal–nanocarbon interfaces

Correlations between magnetic properties and bond formation in Rh–MgO(0 0 1)

Interface magnetism of3dtransition metals

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