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Koplovitz G, Leitus G, Ghosh S, Bloom BP, Yochelis S, Rotem D, Vischio F, Striccoli M, Fanizza E, Naaman R, Waldeck DH, Porath D, Paltiel Y. Single Domain 10 nm Ferromagnetism Imprinted on Superparamagnetic Nanoparticles Using Chiral Molecules. Small 2019; 15:e1804557. [PMID: 30462882 DOI: 10.1002/smll.201804557] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Indexed: 05/19/2023]
Abstract
The rapid growth in demand for data and the emerging applications of Big Data require the increase of memory capacity. Magnetic memory devices are among the leading technologies for meeting this demand; however, they rely on the use of ferromagnets that creates size reduction limitations and poses complex materials requirements. Usually magnetic memory sizes are limited to 30-50 nm. Reducing the size even further, to the ≈10-20 nm scale, destabilizes the magnetization and its magnetic orientation becomes susceptible to thermal fluctuations and stray magnetic fields. In the present work, it is shown that 10 nm single domain ferromagnetism can be achieved. Using asymmetric adsorption of chiral molecules, superparamagnetic iron oxide nanoparticles become ferromagnetic with an average coercive field of ≈80 Oe. The asymmetric adsorption of molecules stabilizes the magnetization direction at room temperature and the orientation is found to depend on the handedness of the chiral molecules. These studies point to a novel method for the miniaturization of ferromagnets (down to ≈10 nm) using established synthetic protocols.
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Affiliation(s)
- Guy Koplovitz
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Gregory Leitus
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Supriya Ghosh
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Brian P Bloom
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Shira Yochelis
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Dvir Rotem
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Fabio Vischio
- Institute for Chemical and Physical Processes (IPCF) - National Council of Researches CNR, Via Orabona 4, Bari, 70126, Italy
| | - Marinella Striccoli
- Institute for Chemical and Physical Processes (IPCF) - National Council of Researches CNR, Via Orabona 4, Bari, 70126, Italy
| | - Elisabetta Fanizza
- Department of Chemistry, University of Bari, Via Orabona 4, Bari, 70126, Italy
| | - Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - David H Waldeck
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Danny Porath
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Yossi Paltiel
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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Al-Bustami H, Koplovitz G, Primc D, Yochelis S, Capua E, Porath D, Naaman R, Paltiel Y. Single Nanoparticle Magnetic Spin Memristor. Small 2018; 14:e1801249. [PMID: 29952065 DOI: 10.1002/smll.201801249] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/09/2018] [Indexed: 05/21/2023]
Abstract
There is an increasing demand for the development of a simple Si-based universal memory device at the nanoscale that operates at high frequencies. Spin-electronics (spintronics) can, in principle, increase the efficiency of devices and allow them to operate at high frequencies. A primary challenge for reducing the dimensions of spintronic devices is the requirement for high spin currents. To overcome this problem, a new approach is presented that uses helical chiral molecules exhibiting spin-selective electron transport, which is called the chiral-induced spin selectivity (CISS) effect. Using the CISS effect, the active memory device is miniaturized for the first time from the micrometer scale to 30 nm in size, and this device presents memristor-like nonlinear logic operation at low voltages under ambient conditions and room temperature. A single nanoparticle, along with Au contacts and chiral molecules, is sufficient to function as a memory device. A single ferromagnetic nanoplatelet is used as a fixed hard magnet combined with Au contacts in which the gold contacts act as soft magnets due to the adsorbed chiral molecules.
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Affiliation(s)
- Hammam Al-Bustami
- Applied Physics, Hebrew University of Jerusalem, Edmond J Safra Campus, Jerusalem, 919041, Israel
| | - Guy Koplovitz
- Applied Physics, Hebrew University of Jerusalem, Edmond J Safra Campus, Jerusalem, 919041, Israel
| | - Darinka Primc
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Tan Hall 373A, Berkeley, CA, 94720, USA
- Laboratory for Multifunctional Materials, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, Zurich, 8093, Switzerland
| | - Shira Yochelis
- Applied Physics, Hebrew University of Jerusalem, Edmond J Safra Campus, Jerusalem, 919041, Israel
| | - Eyal Capua
- Department of Chemical and Biological Physics, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Danny Porath
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Ron Naaman
- Department of Chemical and Biological Physics, The Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Yossi Paltiel
- Applied Physics, Hebrew University of Jerusalem, Edmond J Safra Campus, Jerusalem, 919041, Israel
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Koplovitz G, Primc D, Ben Dor O, Yochelis S, Rotem D, Porath D, Paltiel Y. Magnetic Nanoplatelet-Based Spin Memory Device Operating at Ambient Temperatures. Adv Mater 2017; 29:1606748. [PMID: 28256757 DOI: 10.1002/adma.201606748] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/16/2017] [Indexed: 06/06/2023]
Abstract
There is an increasing demand for realizing a simple Si based universal memory device working at ambient temperatures. In principle, nonvolatile magnetic memory can operate at low power consumption and high frequencies. However, in order to compete with existing memory technology, size reduction and simplification of the used material systems are essential. In this work, the chiral-induced spin selectivity effect is used along with 30-50 nm ferromagnetic nanoplatelets in order to realize a simple magnetic memory device. The vertical memory is Si compatible, easy to fabricate, and in principle can be scaled down to a single nanoparticle size. Results show clear dual magnetization behavior with threefold enhancement between the one and zero states. The magnetization of the device is accompanied with large avalanche like noise that is ascribed to the redistribution of current densities due to spin accumulation inducing coupling effects between the different nanoplatelets.
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Affiliation(s)
- Guy Koplovitz
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Darinka Primc
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
- Laboratory for Multifunctional Materials, Department of Materials, ETH Zurich, Zurich, 8093, Switzerland
| | - Oren Ben Dor
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Shira Yochelis
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Dvir Rotem
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Danny Porath
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Yossi Paltiel
- Department of Applied Physics, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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