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Tassinari F, Jayarathna DR, Kantor-Uriel N, Davis KL, Varade V, Achim C, Naaman R. Chirality Dependent Charge Transfer Rate in Oligopeptides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706423. [PMID: 29611223 DOI: 10.1002/adma.201706423] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 02/19/2018] [Indexed: 05/21/2023]
Abstract
It is shown that "spontaneous magnetization" occurs when chiral oligopeptides are attached to ferrocene and are self-assembled on a gold substrate. As a result, the electron transfer, measured by electrochemistry, shows asymmetry in the reduction and oxidation rate constants; this asymmetry is reversed between the two enantiomers. The results can be explained by the chiral induced spin selectivity of the electron transfer. The measured magnetization shows high anisotropy and the "easy axis" of magnetization is along the molecular axis.
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Affiliation(s)
- Francesco Tassinari
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | | | - Nirit Kantor-Uriel
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Kathryn L Davis
- Department of Chemistry, Manchester University, North Manchester, IN, 46962, USA
| | - Vaibhav Varade
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Catalina Achim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
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Ben Dor O, Yochelis S, Radko A, Vankayala K, Capua E, Capua A, Yang SH, Baczewski LT, Parkin SSP, Naaman R, Paltiel Y. Magnetization switching in ferromagnets by adsorbed chiral molecules without current or external magnetic field. Nat Commun 2017; 8:14567. [PMID: 28230054 PMCID: PMC5331337 DOI: 10.1038/ncomms14567] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/10/2017] [Indexed: 11/10/2022] Open
Abstract
Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 106 A·cm-2, or about 1 × 1025 electrons s-1 cm-2. This relatively high current density significantly affects the devices' structure and performance. Here we demonstrate magnetization switching of ferromagnetic thin layers that is induced solely by adsorption of chiral molecules. In this case, about 1013 electrons per cm2 are sufficient to induce magnetization reversal. The direction of the magnetization depends on the handedness of the adsorbed chiral molecules. Local magnetization switching is achieved by adsorbing a chiral self-assembled molecular monolayer on a gold-coated ferromagnetic layer with perpendicular magnetic anisotropy. These results present a simple low-power magnetization mechanism when operating at ambient conditions.
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Affiliation(s)
- Oren Ben Dor
- Applied Physics Department and the Center for Nano-Science and Nano-Technology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Shira Yochelis
- Applied Physics Department and the Center for Nano-Science and Nano-Technology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Anna Radko
- Applied Physics Department and the Center for Nano-Science and Nano-Technology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Kiran Vankayala
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Eyal Capua
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Amir Capua
- IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - See-Hun Yang
- IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - Lech Tomasz Baczewski
- Magnetic Heterostructures Laboratory, Institute of Physics Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warszawa, Poland
| | - Stuart Stephen Papworth Parkin
- IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
- Max Planck Institute for Microstructure Physics, Halle (Saale) D-06120, Germany
| | - Ron Naaman
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yossi Paltiel
- Applied Physics Department and the Center for Nano-Science and Nano-Technology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
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Pichon BP, Pauly M, Marie P, Leuvrey C, Begin-Colin S. Tunable magnetic properties of nanoparticle two-dimensional assemblies addressed by mixed self-assembled monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6235-6243. [PMID: 21495667 DOI: 10.1021/la105052z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Assemblies of magnetic nanoparticles (NPs) are intensively studied due to their high potential applications in spintronic, magnetic and magneto-electronic. The fine control over NP density, interdistance, and spatial arrangement onto substrates is of key importance to govern the magnetic properties through dipolar interactions. In this study, magnetic iron oxide NPs have been assembled on surfaces patterned with self-assembled monolayers (SAMs) of mixed organic molecules. The modification of the molar ratio between coadsorbed 11-mercaptoundecanoic acid (MUA) and mercaptododecane (MDD) on gold substrates is shown to control the size of NPs domains and thus to modulate the characteristic magnetic properties of the assemblies. Moreover, NPs can be used to indirectly probe the structure of SAMs in domains at the nanometer scale.
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Affiliation(s)
- Benoit P Pichon
- Institut de Physique et de Chimie des Matériaux de Strasbourg, 23 rue du Loess-BP 43, 67034 Strasbourg Cedex 2, France.
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