Unexpected Magnetic Properties of Gas-Stabilized Platinum Nanostructures in the Tunneling Regime

Céspedes, Oscar; Wheeler, May; Moorsom, Timothy; Viret, M.

doi:10.1021/nl504254d

Cited by 8 publications

(11 citation statements)

References 49 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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“…For instance, oxygen (O) atoms are expected to be incorporated in the chains, as predicted in several previous works. [7][8][9][10][11][12] Due to outstanding experimental achievements in the last decades, it is nowadays possible to design nanodevices as tools for detecting nanomagnetism by conductance measurements through atomic metal contacts. One can indirectly sense the presence of magnetism by detecting zerobias anomalies, usually originated in the Kondo screening of the spin, if a magnetic impurity is bridging the contact.…”

Section: Introductionmentioning

confidence: 99%

Kondo physics in a Ni impurity embedded in O-doped Au chains

et al. 2015

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By means of ab initio calculations we study the effect of O-doping of Au chains containing a nanocontact represented by a Ni atom as a magnetic impurity. In contrast to pure Au chains, we find that with a minimun O-doping the $5d_{xz,yz}$ states of Au are pushed up, crossing the Fermi level. We also find that for certain O configurations, the Ni atom has two holes in the degenerate $3d_{xz,yz}$ orbitals, forming a spin $S=1$ due to a large Hund interaction. The coupling between the $5d_{xz,yz}$ Au bands and the $3d_{xz,yz}$ of Ni states leads to a possible realization of a two-channel $S=1$ Kondo effect. While this kind of Kondo effect is commonly found in bulk systems, it is rarely observed in low dimensions. The estimated Kondo scale of the system lies within the present achievable experimental resolution in transport measurements. Another possible scenario for certain atomic configurations is that one of the holes resides in a $3d_{z^2}$ orbital, leading to a two-stage Kondo effect, the second one with SU(4) symmetry

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“…Among these adsorbates we have specially chosen the oxygen in this study for the following reasons: (i) from the experimental point of view, the absorption of a very small amount of oxygen is certainly unavoidable during the growth process, and this can happen even under high vacuum conditions, (ii) most first principles calculations on DMI were focused on clean surfaces without oxidants, and (iii) since the oxygen is an electronegative atom, the charge transfer toward oxygen should be significant and, consequently, the interfacial electric dipole moment can be easily tuned by the degree of surface oxidation. In this context, the presence of oxygen at the surface should not be considered as a serious obstacle for growing magnetic nanodevices, but it can prove very useful as a tunable parameter for the functionalization of their magnetic interactions [95,96,97]. For instance, the oxidation of CoFeB layer at certain level of oxygen coverage can greatly tune the magnetic anisotropy [98,99], magnetoresistance properties [100,101], and spin-orbit torque [102].…”

Section: Controlling Dmimentioning

confidence: 99%

Spin-Orbitronics at Transition Metal Interfaces

Manchon

Belabbes

2017

Solid State Physics

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The presence of large spin-orbit interaction at transition metal interfaces enables the emergence of a variety of fascinating phenomena that have been at the forefront of spintronics research in the past ten years. The objective of the present Chapter is to offer a review of these various effects from a theoretical perspective, with a particular focus on spin transport, chiral magnetism and their interplay. After a brief description of the orbital hybridization scheme at transition metal interfaces, we address the impact of spin-orbit coupling on the interfacial magnetic configuration, through the celebrated Dzyaloshinskii-Moriya interaction. We then discuss the physics of spin transport and subsequent torques occurring at these interfaces. We particularly address the spin Hall, spin swapping and inverse spin galvanic effects. Finally, the interplay between flowing charges and chiral magnetic textures as well as their induced dynamics are presented. We conclude this chapter by proposing some perspectives on promising research directions.

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Unexpected Magnetic Properties of Gas-Stabilized Platinum Nanostructures in the Tunneling Regime

Cited by 8 publications

References 49 publications

Emergent magnetism at transition-metal–nanocarbon interfaces

Emergent magnetism at transition-metal–nanocarbon interfaces

Kondo physics in a Ni impurity embedded in O-doped Au chains

Spin-Orbitronics at Transition Metal Interfaces

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