Magnetic memory of a single-molecule quantum magnet wired to a gold surface

Mannini, Matteo; Pineider, Francesco; Sainctavit, Philippe; Danieli, Chiara; Otero, Edwige; Sciancalepore, Corrado; Talarico, Anna; Arrio, Marie‐Anne; Cornia, Andrea; Gatteschi, Dante; Sessoli, Roberta

doi:10.1038/nmat2374

Cited by 1,066 publications

(793 citation statements)

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“…Recently, molecular junctions based on single-molecule magnets ͑SMMs͒ connected to electrodes or monolayers of SMMs at surfaces, have been fabricated and their electron-transport characteristics [1][2][3][4][5][6] have been measured, as well as their mechanical, electronic, and magnetic properties. [7][8][9][10][11][12][13] Electron transport through an SMM drew a lot of attention because of the intriguing interplay between its transport properties and the internal magnetic degrees of freedom, which is absent in transport through small organic molecules. An SMM consists of several transition metal ions interacting through organic or inorganic ligands via superexchange interactions.…”

Section: Introductionmentioning

confidence: 99%

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

et al. 2010

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We examine theoretically coherent electron transport through the single-molecule magnet Mn 12 , bridged between Au͑111͒ electrodes, using the nonequilibrium Green's function method and the density-functional theory. We analyze the effects of bonding type, molecular orientation, and geometry relaxation on the electronic properties and charge and spin transport across the single-molecule junction. We consider nine interface geometries leading to five bonding mechanisms and two molecular orientations: ͑i͒ Au-C bonding, ͑ii͒ Au-Au bonding, ͑iii͒ Au-S bonding, ͑iv͒ Au-H bonding, and ͑v͒ physisorption via van der Waals forces. The two molecular orientations of Mn 12 correspond to the magnetic easy axis of the molecule aligned perpendicular ͓hereafter denoted as orientation ͑1͔͒ or parallel ͓orientation ͑2͔͒ to the direction of electron transport. We find that the electron transport is carried by the lowest unoccupied molecular orbital ͑LUMO͒ level in all the cases that we have simulated. Relaxation of the junction geometries mainly shifts the relevant occupied molecular levels toward the Fermi energy as well as slightly reduces the broadening of the LUMO level. As a result, the current slightly decreases at low bias voltage. Our calculations also show that placing the molecule in the orientation ͑1͒ broadens the LUMO level much more than in the orientation ͑2͒ due to the internal structure of the Mn 12 . Consequently, junctions with the former orientation yield a higher current than those with the latter. Among all of the bonding types considered, the Au-C bonding gives rise to the highest current ͑about one order of magnitude higher than the Au-S bonding͒, for a given distance between the electrodes. The current through the junction with other bonding types decreases in the order of Au-Au, Au-S, and Au-H. Importantly, the spin-filtering effect in all the nine geometries stays robust and their ratios of the majority-spin to the minorityspin transmission coefficients are in the range of 10 3 -10 8 . The general trend in transport among the different bonding types and molecular orientations obtained from this study may be applicable to other single-molecule magnets.

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Section: Introductionmentioning

confidence: 99%

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

et al. 2010

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“…There is growing interest in x-ray magnetic circular dichroism (XMCD) to study SMMs because of its ability to detect element-resolved magnetic moments combined with submonolayer sensitivity. [9][10][11][12][13][14] XMCD has been used to observe magnetic hysteresis, i.e., nonequilibrium magnetization in SMMs. [11][12][13] Here, we demonstrate that in endohedral SMMs the x-ray exposure itself can lead to an acceleration of magnetization relaxation.…”

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X-ray induced demagnetization of single-molecule magnets

Dreiser

Westerström

Piamonteze

et al. 2014

Applied Physics Letters

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Low-temperature x-ray magnetic circular dichroism measurements on the endohedral singlemolecule magnet DySc2N@C80 at the Dy M4,5 edges reveal a shrinking of the opening of the observed hysteresis with increasing x-ray flux. Time-dependent measurements show that the exposure of the molecules to x-rays resonant with the Dy M5 edge accelerates the relaxation of magnetization more than off-resonant x-rays. The results cannot be explained by a homogeneous temperature rise due to x-ray absorption. Moreover, the observed large demagnetization cross sections indicate that the resonant absorption of one x-ray photon induces the demagnetization of many molecules.

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“…The use of spin as the information conveying entity has stirred much excitement due to its extraordinary properties of information storage, speed, and low-energy consumption [1][2][3]. Miniaturization is quickly proceeding, reaching very small domain-wall devices [4], atomic-size devices [5], and the realm of molecular devices [2,[6][7][8][9]. Among all these possibilities, antiferromagnetically (AFM) coupled devices have recently received a lot of attention.…”

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confidence: 99%

Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

et al. 2013

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The controlled switching between two quasistable Néel states in adsorbed antiferromagnetic Fe chains has recently been achieved by Loth et al. [Science 335, 196 (2012)] using tunneling electrons from an STM tip. In order to rationalize their data, we evaluate the rate of tunneling electron-induced switching between the Néel states. Good agreement is found with the experiment, permitting us to identify three switching mechanisms: (i) The search for nanoscale electronic devices has prompted intense research in the field of nanomagnetism. The use of spin as the information conveying entity has stirred much excitement due to its extraordinary properties of information storage, speed, and low-energy consumption [1][2][3]. Miniaturization is quickly proceeding, reaching very small domain-wall devices [4], atomic-size devices [5], and the realm of molecular devices [2,[6][7][8][9]. Among all these possibilities, antiferromagnetically (AFM) coupled devices have recently received a lot of attention. The AFM characteristics make these devices very well fitted for quantum computation since they naturally involved entangled states [10,11]. Moreover, the storage in AFM devices is particularly robust due to the lack of a total magnetic moment. However, this robustness has deterred their use because changing their magnetic state becomes difficult [12].Recently, Loth and co-workers succeeded in controllably switching the spin states of AFM atomic chains [12]. Two quasistable Néel states, exhibiting alternating spin directions on the atoms along the chain, were evidenced in Fe chains adsorbed on a CuN=Cuð100Þ surface. Loth and co-workers showed that the Néel states can be switched by tunneling electrons injected from a polarized scanning tunneling microscope (STM) tip into one of the atoms of the chain. This demonstrated the possibility of storing information on the atomic-scale antiferromagnet. Theoretical predictions show that writing and reading spin states entail fundamental problems associated with the quantum nature of the process [13]. Spin manipulation by tunneling electrons has been pictured as due to a spintorque mechanism where spin angular momentum from the electron is transferred into the atomic spin system [14][15][16]. However, due to the lack of magnetic moment in AFM systems, spin manipulation must follow a different mechanism. Unavoidably, spin manipulations and excitations are closely related [17]. Indeed, switching between Néel states has been experimentally associated with overcoming an activation energy [12]. However, in the case of degenerate Néel states, resonant transitions should be expected. Hence, the experimental data raise many questions regarding the possibility of resonant switching, the efficiency of activated switching, the nature of the involved excitations, and the physics at play in AFM spin torque. In summary, a complete view of the switching process is missing.In this Letter, we reveal the switching mechanisms at play in the experiment of Ref. [12]. The mechanisms turn out to be rich and ...

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Magnetic memory of a single-molecule quantum magnet wired to a gold surface

Cited by 1,066 publications

References 28 publications

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

X-ray induced demagnetization of single-molecule magnets

Correlation-Mediated Processes for Electron-Induced Switching between Néel States of Fe Antiferromagnetic Chains

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