1
|
Corradini V, Candini A, Klar D, Biagi R, De Renzi V, Lodi Rizzini A, Cavani N, Del Pennino U, Klyatskaya S, Ruben M, Velez-Fort E, Kummer K, Brookes NB, Gargiani P, Wende H, Affronte M. Probing magnetic coupling between LnPc 2 (Ln = Tb, Er) molecules and the graphene/Ni (111) substrate with and without Au-intercalation: role of the dipolar field. Nanoscale 2017; 10:277-283. [PMID: 29210429 DOI: 10.1039/c7nr06610d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Lanthanides (Ln) bis-phthalocyanine (Pc), the so-called LnPc2double decker, are a promising class of molecules with a well-defined magnetic anisotropy. In this work, we investigate the magnetic properties of LnPc2 molecules UHV-deposited on a graphene/Ni(111) substrate and how they modify when an Au layer is intercalated between Ni and graphene. X-ray absorption spectroscopy (XAS), and linear and magnetic circular dichroism (XLD and XMCD) were used to characterize the systems and probe the magnetic coupling between LnPc2 molecules and the Ni substrate through graphene, both gold-intercalated and not. Two types of LnPc2 molecules (Ln = Tb, Er) with a different magnetic anisotropy (easy-axis for Tb, easy-plane for Er) were considered. XMCD shows an antiferromagnetic coupling between Ln and Ni(111) even in the presence of the graphene interlayer. Au intercalation causes the vanishing of the interaction between Tb and Ni(111). In contrast, in the case of ErPc2, we found that the gold intercalation does not perturb the magnetic coupling. These results, combined with the magnetic anisotropy of the systems, suggest the possible importance of the magnetic dipolar field contribution for determining the magnetic behaviour.
Collapse
Affiliation(s)
- V Corradini
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
2
|
Candini A, Klar D, Marocchi S, Corradini V, Biagi R, De Renzi V, Del Pennino U, Troiani F, Bellini V, Klyatskaya S, Ruben M, Kummer K, Brookes NB, Huang H, Soncini A, Wende H, Affronte M. Spin-communication channels between Ln(III) bis-phthalocyanines molecular nanomagnets and a magnetic substrate. Sci Rep 2016; 6:21740. [PMID: 26907811 PMCID: PMC4764849 DOI: 10.1038/srep21740] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/25/2016] [Indexed: 12/03/2022] Open
Abstract
Learning the art of exploiting the interplay between different units at the atomic scale is a fundamental step in the realization of functional nano-architectures and interfaces. In this context, understanding and controlling the magnetic coupling between molecular centers and their environment is still a challenging task. Here we present a combined experimental-theoretical work on the prototypical case of the bis(phthalocyaninato)-lanthanide(III) (LnPc2) molecular nanomagnets magnetically coupled to a Ni substrate. By means of X-ray magnetic circular dichroism we show how the coupling strength can be tuned by changing the Ln ion. The microscopic parameters of the system are determined by ab-initio calculations and then used in a spin Hamiltonian approach to interpret the experimental data. By this combined approach we identify the features of the spin communication channel: the spin path is first realized by the mediation of the external (5d) electrons of the Ln ion, keeping the characteristic features of the inner 4 f orbitals unaffected, then through the organic ligand, acting as a bridge to the external world.
Collapse
Affiliation(s)
- A Candini
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy
| | - D Klar
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstraße 1, D-47048 Duisburg, Germany
| | - S Marocchi
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy
| | - V Corradini
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy
| | - R Biagi
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy.,Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia via G. Campi 213/A, 41125 Modena, Italy
| | - V De Renzi
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy.,Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia via G. Campi 213/A, 41125 Modena, Italy
| | - U Del Pennino
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy.,Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia via G. Campi 213/A, 41125 Modena, Italy
| | - F Troiani
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy
| | - V Bellini
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy
| | - S Klyatskaya
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany
| | - M Ruben
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), D-76344 Eggenstein-Leopoldshafen, Germany.,Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 UdS-CNRS, 67034 Strasbourg Cedex 2, France
| | - K Kummer
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38043 Grenoble, France
| | - N B Brookes
- European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, 38043 Grenoble, France
| | - H Huang
- School of Chemistry, The University of Melbourne, 3010 Victoria, Australia
| | - A Soncini
- School of Chemistry, The University of Melbourne, 3010 Victoria, Australia
| | - H Wende
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstraße 1, D-47048 Duisburg, Germany
| | - M Affronte
- Centro S3, Istituto Nanoscienze - CNR, via G. Campi 213/A, 41125 Modena, Italy.,Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia via G. Campi 213/A, 41125 Modena, Italy
| |
Collapse
|
3
|
Lumetti S, Candini A, Godfrin C, Balestro F, Wernsdorfer W, Klyatskaya S, Ruben M, Affronte M. Single-molecule devices with graphene electrodes. Dalton Trans 2016; 45:16570-16574. [DOI: 10.1039/c6dt02445a] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Design, fabrication and low temperature characterization of a molecular spin transistor made of graphene electrodes and a TbPc2 molecular dot are reported.
Collapse
Affiliation(s)
- S. Lumetti
- Istituto Nanoscienze – CNR
- Centro S3 Modena
- 41124 Modena
- Italy
- Dipartimento di Scienze Fisiche
| | - A. Candini
- Istituto Nanoscienze – CNR
- Centro S3 Modena
- 41124 Modena
- Italy
| | - C. Godfrin
- Université Grenoble Alpes
- Institut Néel
- F-38042 Grenoble
- France
- CNRS
| | - F. Balestro
- Université Grenoble Alpes
- Institut Néel
- F-38042 Grenoble
- France
- CNRS
| | - W. Wernsdorfer
- Université Grenoble Alpes
- Institut Néel
- F-38042 Grenoble
- France
- CNRS
| | - S. Klyatskaya
- Institute of Nanotechnology
- Karlsruhe Institute of Technology (KIT)
- D-76344 Eggenstein-Leopoldshafen
- Germany
| | - M. Ruben
- Institute of Nanotechnology
- Karlsruhe Institute of Technology (KIT)
- D-76344 Eggenstein-Leopoldshafen
- Germany
- Institut de Physique et Chimie des Matériaux de Strasbourg
| | - M. Affronte
- Istituto Nanoscienze – CNR
- Centro S3 Modena
- 41124 Modena
- Italy
- Dipartimento di Scienze Fisiche
| |
Collapse
|
4
|
Paolicelli G, Tripathi M, Corradini V, Candini A, Valeri S. Nanoscale frictional behavior of graphene on SiO₂ and Ni(111) substrates. Nanotechnology 2015; 26:055703. [PMID: 25581391 DOI: 10.1088/0957-4484/26/5/055703] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Friction characteristics of graphene deposited on different substrates have been studied by atomic force microscopy (AFM). In particular, we compared mechanically exfoliated graphene transferred over Si/SiO₂ with respect to monolayer (ML) graphene grown in our laboratory by low temperature chemical vapor deposition on Ni(111) single crystal. Friction force measurements by AFM have been carried out as function of load under different environment conditions, namely vacuum (10(-5) Torr), nitrogen and air. The typical decrease of friction force with increasing number of layers has been observed on graphene over Si/SiO₂ in all environment including vacuum. Continuum mechanical approximation has been used to analyze the friction versus load curves of ML graphene on Ni(111). Analysis shows that Derjaguin-Mueller-Toporov model is in good agreement with our experimental data indicating that overall behavior of the interface graphene-Ni(111) is relatively rigid respect to out of plane deformations. This result is consistent with the structural characteristics of the interface since graphene grows in registry with Ni(111) surface with covalent bonding character. Finally, the shear strength and the work of adhesion of the two systems with respect to AFM tip in vacuum have been compared. The result of this procedure indicates that shear strength and work of adhesion measured on graphene-Si/SiO₂ interface are always greater than those on graphene-Ni(111) interface.
Collapse
Affiliation(s)
- G Paolicelli
- CNR, Istituto Nanoscienze-Centro S3 Via Campi 213/a, I-41125 Modena, Italy
| | | | | | | | | |
Collapse
|
5
|
Bellini V, Lorusso G, Candini A, Wernsdorfer W, Faust TB, Timco GA, Winpenny REP, Affronte M. Propagation of spin information at the supramolecular scale through heteroaromatic linkers. Phys Rev Lett 2011; 106:227205. [PMID: 21702630 DOI: 10.1103/physrevlett.106.227205] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Indexed: 05/31/2023]
Abstract
We report an in-depth study on how spin information propagates at supramolecular scale through a family of heteroaromatic linkers. By density-functional theory calculations, we rationalize the behavior of a series of Cr7Ni dimers for which we are able to systematically change the aromatic linker thus tuning the strength of the magnetic interaction, as experimentally shown by low temperature micro-SQUID and specific heat measurements. We also predict a cos2 dependence of the magnetic coupling on the twisting angle between the aromatic cycles in bicyclic linkers, a mechanism parallel to charge transport on similar systems [L. Venkataraman et al., Nature (London) 442, 904 (2006)].
Collapse
Affiliation(s)
- V Bellini
- S3-Institute Nanoscience-CNR, Via Campi 213/A, 41125 Modena, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Abstract
Molecular spin clusters are mesoscopic systems whose structural and physical features can be tailored at the synthetic level. Besides, their quantum behavior is directly accessible in the laboratory and their magnetic properties can be rationalized in terms of microscopic spin models. Thus they represent an ideal playground within solid state systems to test concepts in quantum mechanics. One intriguing challenge is to control entanglement between molecular spins. Here we show how this goal can be pursued by discussing specific examples and referring to recent achievements.
Collapse
Affiliation(s)
- F Troiani
- CNR Institute of nanoSciences S3, Università di Modena e Reggio Emilia, via Campi 213/a, I-41125 Modena, Italy
| | | | | | | | | |
Collapse
|
7
|
Candini A, Lorusso G, Troiani F, Ghirri A, Carretta S, Santini P, Amoretti G, Muryn C, Tuna F, Timco G, McInnes EJL, Winpenny REP, Wernsdorfer W, Affronte M. Entanglement in supramolecular spin systems of two weakly coupled antiferromagnetic rings (purple-Cr7Ni). Phys Rev Lett 2010; 104:037203. [PMID: 20366678 DOI: 10.1103/physrevlett.104.037203] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 08/28/2009] [Indexed: 05/29/2023]
Abstract
We characterize supramolecular magnetic structures, consisting of two weakly coupled antiferromagnetic rings, by low-temperature specific heat, susceptibility, magnetization and electron paramagnetic resonance measurements. Intra- and inter-ring interactions are modeled through a microscopic spin-Hamiltonian approach that reproduces all the experimental data quantitatively and legitimates the use of an effective two-qubit picture. Spin entanglement between the rings is experimentally demonstrated through magnetic susceptibility below 50 mK and theoretically quantified by the concurrence.
Collapse
Affiliation(s)
- A Candini
- National Research Center on nanoStructures and bioSystems at Surfaces (S3), CNR-INFM, 41100 Modena, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Carretta S, Santini P, Amoretti G, Affronte M, Candini A, Ghirri A, Tidmarsh IS, Laye RH, Shaw R, McInnes EJL. High-temperature slow relaxation of the magnetization in Ni10 magnetic molecules. Phys Rev Lett 2006; 97:207201. [PMID: 17155708 DOI: 10.1103/physrevlett.97.207201] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Indexed: 05/12/2023]
Abstract
We investigate a family of molecular crystals containing noninteracting Ni10 magnetic molecules. We find slow relaxation of the magnetization below a temperature as high as 17 K and we show that this behavior is not associated with an anisotropy energy barrier. Ni10 has a characteristic magnetic energy spectrum structured in dense bands, the lowest of which makes the crystal opaque to phonons of energy below about 1 meV. We ascribe the nonequilibrium behavior to the resulting resonant trapping of these low-energy phonons. Trapping breaks up spin relaxation paths leading to a novel kind of slow magnetic dynamics which occurs in the lack of anisotropy, magnetic interactions and quenched disorder.
Collapse
Affiliation(s)
- S Carretta
- Dipartimento di Fisica, Università di Parma, I-43100 Parma, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Evangelisti M, Candini A, Ghirri A, Affronte M, Powell GW, Gass IA, Wood PA, Parsons S, Brechin EK, Collison D, Heath SL. Tunable dipolar magnetism in high-spin molecular clusters. Phys Rev Lett 2006; 97:167202. [PMID: 17155429 DOI: 10.1103/physrevlett.97.167202] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 07/12/2006] [Indexed: 05/12/2023]
Abstract
We report on the Fe17 high-spin molecular cluster and show that this system is an exemplification of nanostructured dipolar magnetism. Each Fe17 molecule, with spin S=35/2 and axial anisotropy as small as D approximately -0.02 K, is the magnetic unit that can be chemically arranged in different packing crystals while preserving both the spin ground state and anisotropy. For every configuration, molecular spins are correlated only by dipolar interactions. The ensuing interplay between dipolar energy and anisotropy gives rise to macroscopic behaviors ranging from superparamagnetism to long-range magnetic order at temperatures below 1 K.
Collapse
Affiliation(s)
- M Evangelisti
- National Research Center on nanoStructures and bioSystems at Surfaces (S3), INFM-CNR, Modena, Italy.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|