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K NA, Kumar S. Ion Selectivity in Multilayered Stacked Nanoporous Graphene. ACS APPLIED MATERIALS & INTERFACES 2024; 16:5294-5301. [PMID: 38236663 DOI: 10.1021/acsami.3c15044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Nanoporous graphene is an ideal candidate for molecular filtration as it can potentially combine high permeability with high selectivity at molecular levels. To make use of graphene in filtration setups, the defects formed during its growth and during the transfer of graphene to the carrier support pose a challenge. These uncontrolled pores can be avoided by stacking graphene layers, and then, controlled pores can be initiated with oxygen plasma. Here, we show that two-layer stacks provide the best balance of defect coverage and high selectivity compared with other stacks. Using the electrical characterization of ionic solutions in the standard diffusion cell, we compare the ionic transport and ionic selectivity of up to three-layered stacks of graphene that have been plasma-treated. We find that there is a decrease in the ionic selectivity of a two-layered stack as one more layer of graphene is added. We provide a model for this occurrence. Our results will be helpful for making practical and high-performance filtration systems from two-dimensional materials.
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Affiliation(s)
- Niketa A K
- Department of Electrical Engineering, Indian Institute of Technology Hyderabad, Hyderabad 502284, Telangana, India
| | - Shishir Kumar
- Department of Electrical Engineering, Indian Institute of Technology Hyderabad, Hyderabad 502284, Telangana, India
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2
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Tie M, Colford S, Niewczas M, Baumbach R, Dhirani AA. Widely Varying Kondo and Magnetic Interactions in Molecule Gold Nanostructured Materials by Changing the Gold Nanoarchitecture. NANO LETTERS 2023; 23:3724-3730. [PMID: 37115852 DOI: 10.1021/acs.nanolett.2c04918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Delocalized-localized electron interactions are central to strongly correlated electron phenomena. Here, we study the Kondo effect, a prototypical strongly correlated phenomena, in a tunable fashion using gold nanostructures (nanoparticle, NP, and nanoshell, NS) + molecule cross-linkers (butanedithiol, BDT). NP films exhibit hallmark signatures of the Kondo effect, including (1) a log temperature resistance upturn as temperature decreases in a metallic regime, and (2) zero-bias conductance peaks (ZBCPs) that are well fit by a Frota function near a percolation insulator transition, previously used to model Kondo peaks observed using tunnel junctions. Remarkably, NP + NS films exhibit ZBCPs that persist to >220 K, i.e., >10-fold higher than that in NP films. Magnetic measurements reveal that moments in NP powders align, and in NS powders, they antialign at low temperatures. Based on these observations, we propose a mechanism in which varying such material nanobuilding blocks can modify electron-electron interactions to such a large degree.
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Affiliation(s)
- Monique Tie
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Sean Colford
- Department of Physics, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Marek Niewczas
- Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7, Canada
| | - Ryan Baumbach
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Al-Amin Dhirani
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- Department of Physics, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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Gamou H, Shimose K, Enoki R, Minamitani E, Shiotari A, Kotani Y, Toyoki K, Nakamura T, Sugimoto Y, Kohda M, Nitta J, Miwa S. Detection of Spin Transfer from Metal to Molecule by Magnetoresistance Measurement. NANO LETTERS 2020; 20:75-80. [PMID: 31820649 DOI: 10.1021/acs.nanolett.9b03110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Localized electronic spin state in molecules has a relatively long spin lifetime and has thus attracted much attention. In this study, we characterize the magnetoresistance of a system comprising Pt and Fe(II)-phthalocyanine (FePc) molecules. The magnetoresistance measurement with the weak antilocalization analysis reveals that a magnetic moment in FePc acts as magnetic impurities for conduction electrons in Pt. Moreover, we find that the magnetoresistance involves a component that possesses the same symmetry as spin-Hall magnetoresistance. These results reveal the spin-angular momentum transfer from metallic Pt to a magnetic moment in FePc molecules, which can be used as a spin torque in a molecular system.
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Affiliation(s)
- Hiromu Gamou
- Department of Materials Science , Tohoku University , Sendai , Miyagi 980-8579 , Japan
| | - Koki Shimose
- Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
| | - Ryoto Enoki
- Department of Materials Science , Tohoku University , Sendai , Miyagi 980-8579 , Japan
| | - Emi Minamitani
- Department of Theoretical and Computational Molecular Science , Institute for Molecular Science , Okazaki , Aichi 444-8585 , Japan
- Department of Materials Engineering , The University of Tokyo , Bunkyo , Tokyo 113-8656 , Japan
| | - Akitoshi Shiotari
- Department of Advanced Materials Science , The University of Tokyo , Kashiwa , Chiba 277-8561 , Japan
| | - Yoshinori Kotani
- Japan Synchrotron Radiation Research Institute , Sayo , Hyogo 679-5198 , Japan
| | - Kentaro Toyoki
- Japan Synchrotron Radiation Research Institute , Sayo , Hyogo 679-5198 , Japan
| | - Tetsuya Nakamura
- Japan Synchrotron Radiation Research Institute , Sayo , Hyogo 679-5198 , Japan
| | - Yoshiaki Sugimoto
- Department of Advanced Materials Science , The University of Tokyo , Kashiwa , Chiba 277-8561 , Japan
| | - Makoto Kohda
- Department of Materials Science , Tohoku University , Sendai , Miyagi 980-8579 , Japan
- Center for Spintronics Research Network , Tohoku University , Sendai , Miyagi 980-8577 , Japan
- Center for Science and Innovation in Spintronics (Core Research Cluster) Organization for Advanced Studies , Tohoku University , Sendai , Miyagi 980-8577 , Japan
| | - Junsaku Nitta
- Department of Materials Science , Tohoku University , Sendai , Miyagi 980-8579 , Japan
- Center for Spintronics Research Network , Tohoku University , Sendai , Miyagi 980-8577 , Japan
- Center for Science and Innovation in Spintronics (Core Research Cluster) Organization for Advanced Studies , Tohoku University , Sendai , Miyagi 980-8577 , Japan
| | - Shinji Miwa
- Graduate School of Engineering Science , Osaka University , Toyonaka , Osaka 560-8531 , Japan
- The Institute for Solid State Physics , The University of Tokyo , Kashiwa , Chiba 277-8581 , Japan
- Center for Spintronics Research Network , Osaka University , Toyonaka , Osaka 560-8531 , Japan
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Tie M, Gravelsins S, Niewczas M, Dhirani AA. Large Kondo effect in assemblies of Au nanoparticles linked with alkanedithiol electron bridges. NANOSCALE 2019; 11:5395-5401. [PMID: 30849159 DOI: 10.1039/c8nr09280j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Using a prototypical nanoparticle-molecule assembly, namely alkanedithiol-linked gold nanoparticle films, we observe hallmark signatures of the Kondo effect in conductance vs. voltage as well as temperature measurements. Its contribution to temperature dependence of conductance is much larger than those from all other temperature-dependant effects up to 300 K by >20-fold - much larger than previous reports of the Kondo effect using other platforms. We find that previous models of the Kondo effect describe our data even in this regime. Given the synthetic control available over nanoparticle properties such as surface area, shape, and chemical composition, our work points to combining flexibility afforded by molecule + nanoparticle assemblies as a powerful way to generate materials exhibiting strong spin-electron interactions.
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Affiliation(s)
- Monique Tie
- Department of Chemistry, University of Toronto, Ontario, CanadaM5S 3H6.
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Jo J, Byun J, Oh I, Park J, Jin MJ, Min BC, Lee J, Yoo JW. Molecular Tunability of Magnetic Exchange Bias and Asymmetrical Magnetotransport in Metalloporphyrin/Co Hybrid Bilayers. ACS NANO 2019; 13:894-903. [PMID: 30557507 DOI: 10.1021/acsnano.8b08689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Individual molecular spins are promising quantum states for emerging computation technologies. The "on surface" configuration of molecules in proximity to a magnetic film allows control over the orientations of molecular spins and coupling between them. The stacking of planar molecular spins could favor antiferromagnetic interlayer couplings and lead to pinning of the magnetic underlayer via the exchange bias, which is extensively utilized in ultrafast and high-density spintronics. However, fundamental understanding of the molecular exchange bias and its operating features on a device has not been unveiled. Here, we showed tunable molecular exchange bias and its asymmetrical magnetotransport characteristics on a device by using the metalloporphyrin/cobalt hybrid films. A series of the distinctive molecular layers showcased a wide range of the interfacial exchange coupling and bias. The transport behaviors of the hybrid bilayer films revealed the molecular exchange bias effect on a fabricated device, representing asymmetric characteristics on anisotropic and angle-dependent magnetoresistances. Theoretical simulations demonstrated close correlations among the interfacial distance, magnetic interaction, and exchange bias. This study of the hybrid interfacial coupling and its impact on magnetic and magnetotransport behaviors will extend functionalities of molecular spinterfaces for emerging information technologies.
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Affiliation(s)
- Junhyeon Jo
- School of Materials Science and Engineering/Low-Dimensional Carbon Materials Center , Ulsan National Institute of Science and Technology , Ulsan 44919 , Korea
| | - Jinho Byun
- Department of Physics , Pusan National University , Busan 46241 , Korea
| | - Inseon Oh
- School of Materials Science and Engineering/Low-Dimensional Carbon Materials Center , Ulsan National Institute of Science and Technology , Ulsan 44919 , Korea
| | - Jungmin Park
- School of Materials Science and Engineering/Low-Dimensional Carbon Materials Center , Ulsan National Institute of Science and Technology , Ulsan 44919 , Korea
| | - Mi-Jin Jin
- School of Materials Science and Engineering/Low-Dimensional Carbon Materials Center , Ulsan National Institute of Science and Technology , Ulsan 44919 , Korea
| | - Byoung-Chul Min
- Center for Spintronics , Korea Institute of Science and Technology , Seoul 02792 , Korea
| | - Jaekwang Lee
- Department of Physics , Pusan National University , Busan 46241 , Korea
| | - Jung-Woo Yoo
- School of Materials Science and Engineering/Low-Dimensional Carbon Materials Center , Ulsan National Institute of Science and Technology , Ulsan 44919 , Korea
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Liang L, Chen Q, Lu J, Talsma W, Shan J, Blake GR, Palstra TTM, Ye J. Inducing ferromagnetism and Kondo effect in platinum by paramagnetic ionic gating. SCIENCE ADVANCES 2018; 4:eaar2030. [PMID: 29740612 PMCID: PMC5938224 DOI: 10.1126/sciadv.aar2030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
Electrically controllable magnetism, which requires the field-effect manipulation of both charge and spin degrees of freedom, has attracted growing interest since the emergence of spintronics. We report the reversible electrical switching of ferromagnetic (FM) states in platinum (Pt) thin films by introducing paramagnetic ionic liquid (PIL) as the gating media. The paramagnetic ionic gating controls the movement of ions with magnetic moments, which induces itinerant ferromagnetism on the surface of Pt films, with large coercivity and perpendicular anisotropy mimicking the ideal two-dimensional Ising-type FM state. The electrical transport of the induced FM state shows Kondo effect at low temperature, suggesting spatially separated coexistence of Kondo scattering beneath the FM interface. The tunable FM state indicates that paramagnetic ionic gating could serve as a versatile method to induce rich transport phenomena combining field effect and magnetism at PIL-gated interfaces.
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Atxabal A, Ribeiro M, Parui S, Urreta L, Sagasta E, Sun X, Llopis R, Casanova F, Hueso LE. Spin doping using transition metal phthalocyanine molecules. Nat Commun 2016; 7:13751. [PMID: 27941810 PMCID: PMC5159905 DOI: 10.1038/ncomms13751] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/31/2016] [Indexed: 11/24/2022] Open
Abstract
Molecular spins have become key enablers for exploring magnetic interactions, quantum information processes and many-body effects in metals. Metal-organic molecules, in particular, let the spin state of the core metal ion to be modified according to its organic environment, allowing localized magnetic moments to emerge as functional entities with radically different properties from its simple atomic counterparts. Here, using and preserving the integrity of transition metal phthalocyanine high-spin complexes, we demonstrate the magnetic doping of gold thin films, effectively creating a new ground state. We demonstrate it by electrical transport measurements that are sensitive to the scattering of itinerant electrons with magnetic impurities, such as Kondo effect and weak antilocalization. Our work expands in a simple and powerful way the classes of materials that can be used as magnetic dopants, opening a new channel to couple the wide range of molecular properties with spin phenomena at a functional scale.
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Affiliation(s)
- A. Atxabal
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - M. Ribeiro
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - S. Parui
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - L. Urreta
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - E. Sagasta
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - X. Sun
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
- CAS Center for Excellence in Nanoscience, Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
| | - R. Llopis
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
| | - F. Casanova
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| | - L. E. Hueso
- CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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Quantum interference measurement of spin interactions in a bio-organic/semiconductor device structure. Sci Rep 2015; 5:9487. [PMID: 25820781 PMCID: PMC4377638 DOI: 10.1038/srep09487] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/04/2015] [Indexed: 02/07/2023] Open
Abstract
Quantum interference is used to measure the spin interactions between an InAs surface electron system and the iron center in the biomolecule hemin in nanometer proximity in a bio-organic/semiconductor device structure. The interference quantifies the influence of hemin on the spin decoherence properties of the surface electrons. The decoherence times of the electrons serve to characterize the biomolecule, in an electronic complement to the use of spin decoherence times in magnetic resonance. Hemin, prototypical for the heme group in hemoglobin, is used to demonstrate the method, as a representative biomolecule where the spin state of a metal ion affects biological functions. The electronic determination of spin decoherence properties relies on the quantum correction of antilocalization, a result of quantum interference in the electron system. Spin-flip scattering is found to increase with temperature due to hemin, signifying a spin exchange between the iron center and the electrons, thus implying interactions between a biomolecule and a solid-state system in the hemin/InAs hybrid structure. The results also indicate the feasibility of artificial bioinspired materials using tunable carrier systems to mediate interactions between biological entities.
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Zhang Y, Soghomonian V, Kallaher RL, Heremans JJ. Antilocalization sensing of interactions between two-dimensional electrons and surface species. CHINESE SCIENCE BULLETIN-CHINESE 2014. [DOI: 10.1007/s11434-013-0035-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Reactivity mapping with electrochemical gradients for monitoring reactivity at surfaces in space and time. Nat Commun 2013; 4:1667. [PMID: 23575671 PMCID: PMC3644076 DOI: 10.1038/ncomms2688] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 03/01/2013] [Indexed: 01/25/2023] Open
Abstract
Studying and controlling reactions at surfaces is of great fundamental and applied interest in, among others, biology, electronics and catalysis. Because reaction kinetics is different at surfaces compared with solution, frequently, solution-characterization techniques cannot be used. Here we report solution gradients, prepared by electrochemical means, for controlling and monitoring reactivity at surfaces in space and time. As a proof of principle, electrochemically derived gradients of a reaction parameter (pH) and of a catalyst (Cu(I)) have been employed to make surface gradients on the micron scale and to study the kinetics of the (surface-confined) imine hydrolysis and the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, respectively. For both systems, the kinetic data were spatially visualized in a two-dimensional reactivity map. In the case of the copper(I)-catalysed azide-alkyne 1,3-dipolar cycloaddition, the reaction order (2) was deduced from it.
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Ataç D, Gang T, Yilmaz MD, Bose SK, Lenferink ATM, Otto C, de Jong MP, Huskens J, van der Wiel WG. Tuning the Kondo effect in thin Au films by depositing a thin layer of Au on molecular spin-dopants. NANOTECHNOLOGY 2013; 24:375204. [PMID: 23975183 DOI: 10.1088/0957-4484/24/37/375204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report on the tuning of the Kondo effect in thin Au films containing a monolayer of cobalt(II) terpyridine complexes by altering the ligand structure around the Co(2+) ions by depositing a thin Au capping layer on top of the monolayer on Au by magnetron sputtering (more energetic) and e-beam evaporation (softer). We show that the Kondo effect is slightly enhanced with respect to that of the uncapped film when the cap is deposited by evaporation, and significantly enhanced when magnetron sputtering is used. The Kondo temperature (TK) increases from 3 to 4.2/6.2 K for the evaporated/sputtered caps. X-ray absorption spectroscopy and surface-enhanced Raman spectroscopy investigation showed that the organic ligands remain intact upon Au e-beam evaporation; however, sputtering inflicts significant change in the Co(2+) electronic environment. The location of the monolayer-on the surface or embedded in the film-has a small effect. However, the damage of Co-N bonds induced by sputtering has a drastic effect on the increase of the impurity-electron interaction. This opens up the way for tuning of the magnetic impurity states, e.g. spin quantum number, binding energy with respect to the host Fermi energy, and overlap via the ligand structure around the ions.
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Affiliation(s)
- D Ataç
- NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands
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