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Darwin E, Tomasello R, Shepley PM, Satchell N, Carpentieri M, Finocchio G, Hickey BJ. Antiferromagnetic interlayer exchange coupled Co 68B 32/Ir/Pt multilayers. Sci Rep 2024; 14:95. [PMID: 38168577 PMCID: PMC10761723 DOI: 10.1038/s41598-023-49976-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Synthetic antiferromagnetic structures can exhibit the advantages of high velocity similarly to antiferromagnets with the additional benefit of being imaged and read-out through techniques applied to ferromagnets. Here, we explore the potential and limits of synthetic antiferromagnets to uncover ways to harness their valuable properties for applications. Two synthetic antiferromagnetic systems have been engineered and systematically investigated to provide an informed basis for creating devices with maximum potential for data storage, logic devices, and skyrmion racetrack memories. The two systems considered are (system 1) CoB/Ir/Pt of N repetitions with Ir inducing the negative coupling between the ferromagnetic layers and (system 2) two ferromagnetically coupled multilayers of CoB/Ir/Pt, coupled together antiferromagnetically with an Ir layer. From the hysteresis, it is found that system 1 shows stable antiferromagnetic interlayer exchange coupling between each magnetic layer up to N = 7. Using Kerr imaging, the two ferromagnetic multilayers in system 2 are shown to undergo separate maze-like switches during hysteresis. Both systems are also studied as a function of temperature and show different behaviors. Micromagnetic simulations predict that in both systems the skyrmion Hall angle is suppressed with the skyrmion velocity five times higher in system 1 than system 2.
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Affiliation(s)
- Emily Darwin
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Riccardo Tomasello
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Philippa M Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Nathan Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- Department of Physics, Texas State University, San Marcos, TX, 78666, USA
| | - Mario Carpentieri
- Department of Electrical and Information Engineering, Politecnico Di Bari, Via E. Orabona 4, 70125, Bari, Italy
| | - Giovanni Finocchio
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, 98166, Messina, Italy.
| | - B J Hickey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK.
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Cubukcu M, Pöllath S, Tacchi S, Stacey A, Darwin E, Freeman CWF, Barton C, Hickey BJ, Marrows CH, Carlotti G, Back CH, Kazakova O. Manipulation of Magnetic Skyrmion Density in Continuous Ir/Co/Pt Multilayers. Micromachines (Basel) 2022; 13:1911. [PMID: 36363931 PMCID: PMC9693305 DOI: 10.3390/mi13111911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
We show that magnetic skyrmions can be stabilised at room temperature in continuous [Ir/Co/Pt]5 multilayers on SiO2/Si substrates without the prior application of electric current or magnetic field. While decreasing the Co thickness, a transition of the magnetic domain patterns from worm-like state to separated stripes is observed. The skyrmions are clearly imaged in both states using magnetic force microscopy. The density of skyrmions can be significantly enhanced after applying the "in-plane field procedure". Our results provide means to manipulate magnetic skyrmion density, further allowing for the optimised engineering of skyrmion-based devices.
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Affiliation(s)
- M. Cubukcu
- National Physical Laboratory, Teddington TW11 0LW, UK
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK
| | - S. Pöllath
- Institut für Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - S. Tacchi
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy
| | - A. Stacey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - E. Darwin
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - C. W. F. Freeman
- National Physical Laboratory, Teddington TW11 0LW, UK
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK
| | - C. Barton
- National Physical Laboratory, Teddington TW11 0LW, UK
| | - B. J. Hickey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - C. H. Marrows
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - G. Carlotti
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy
| | - C. H. Back
- Physik-Department, Technical University Munich, 85748 Garching, Germany
| | - O. Kazakova
- National Physical Laboratory, Teddington TW11 0LW, UK
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Satchell N, Mitchell T, Shepley PM, Darwin E, Hickey BJ, Burnell G. Pt and CoB trilayer Josephson [Formula: see text] junctions with perpendicular magnetic anisotropy. Sci Rep 2021; 11:11173. [PMID: 34045523 PMCID: PMC8159980 DOI: 10.1038/s41598-021-90432-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 04/05/2021] [Indexed: 11/13/2022] Open
Abstract
We report on the electrical transport properties of Nb based Josephson junctions with Pt/Co[Formula: see text]B[Formula: see text]/Pt ferromagnetic barriers. The barriers exhibit perpendicular magnetic anisotropy, which has the main advantage for potential applications over magnetisation in-plane systems of not affecting the Fraunhofer response of the junction. In addition, we report that there is no magnetic dead layer at the Pt/Co[Formula: see text]B[Formula: see text] interfaces, allowing us to study barriers with ultra-thin Co[Formula: see text]B[Formula: see text]. In the junctions, we observe that the magnitude of the critical current oscillates with increasing thickness of the Co[Formula: see text]B[Formula: see text] strong ferromagnetic alloy layer. The oscillations are attributed to the ground state phase difference across the junctions being modified from zero to [Formula: see text]. The multiple oscillations in the thickness range [Formula: see text] nm suggests that we have access to the first zero-[Formula: see text] and [Formula: see text]-zero phase transitions. Our results fuel the development of low-temperature memory devices based on ferromagnetic Josephson junctions.
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Affiliation(s)
- N. Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - T. Mitchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - P. M. Shepley
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - E. Darwin
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - B. J. Hickey
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - G. Burnell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
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Fayne R, Castillo D, Sanchez N, Burroway B, Nanda S, De Bedout V, Stratman S, Rosen J, Darwin E, Nagrani N, Gonzalez A, Paul S, Maderal A, Elgart G, Kirsner R, Nichols A. Dermatology consultation service at a large metropolitan hospital system serving minority populations. J Eur Acad Dermatol Venereol 2020; 34:2120-2126. [DOI: 10.1111/jdv.16565] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/03/2020] [Indexed: 11/30/2022]
Affiliation(s)
- R. Fayne
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - D.E. Castillo
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - N. Sanchez
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - B. Burroway
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - S. Nanda
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - V. De Bedout
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - S. Stratman
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - J. Rosen
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - E. Darwin
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - N. Nagrani
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - A. Gonzalez
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - S. Paul
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - A. Maderal
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - G. Elgart
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - R. Kirsner
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
| | - A. Nichols
- Dr. Philip Frost Department of Dermatology and Cutaneous Surgery University of Miami Miller School of Medicine Miami FL USA
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Jaller J, Darwin E, Lev-Tov H. 352 Validation of inpatient ICD9 diagnosis codes as predictors of venous leg ulcers. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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