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Satchell N, Gupta S, Maheshwari M, Shepley PM, Rogers M, Cespedes O, Burnell G. Thin film epitaxial [111] Co[Formula: see text]Pt[Formula: see text]: structure, magnetisation, and spin polarisation. Sci Rep 2023; 13:12468. [PMID: 37528131 PMCID: PMC10394051 DOI: 10.1038/s41598-023-37825-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 06/28/2023] [Indexed: 08/03/2023] Open
Abstract
Ferromagnetic films with perpendicular magnetic anisotropy are of interest in spintronics and superconducting spintronics. Perpendicular magnetic anisotropy can be achieved in thin ferromagnetic multilayer structures, when the anisotropy is driven by carefully engineered interfaces. Devices with multiple interfaces are disadvantageous for our application in superconducting spintronics, where the current perpendicular to plane is affected by the interfaces. Robust intrinsic PMA can be achieved in certain Co[Formula: see text]Pt[Formula: see text] alloys and compounds at any thickness, without increasing the number of interfaces. Here, we grow equiatomic Co[Formula: see text]Pt[Formula: see text] and report a comprehensive study on the structural, magnetic, and spin-polarisation properties in the [Formula: see text] and [Formula: see text] ordered compounds. Primarily, interest in Co[Formula: see text]Pt[Formula: see text] has been in the [Formula: see text] crystal structure, where layers of Pt and Co are stacked alternately in the [100] direction. There has been less work on [Formula: see text] crystal structure, where the stacking is in the [111] direction. For the latter [Formula: see text] crystal structure, we find magnetic anisotropy perpendicular to the film plane. For the former [Formula: see text] crystal structure, the magnetic anisotropy is perpendicular to the [100] plane, which is neither in-plane or out-of-plane in our samples. We obtain a value for the ballistic spin polarisation of the [Formula: see text] and [Formula: see text] Co[Formula: see text]Pt[Formula: see text] to be [Formula: see text].
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Affiliation(s)
- N. Satchell
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - S. Gupta
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - M. Maheshwari
- 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
| | - M. Rogers
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT UK
| | - O. Cespedes
- 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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González-Ruano C, Caso D, Johnsen LG, Tiusan C, Hehn M, Banerjee N, Linder J, Aliev FG. Superconductivity assisted change of the perpendicular magnetic anisotropy in V/MgO/Fe junctions. Sci Rep 2021; 11:19041. [PMID: 34561472 PMCID: PMC8463706 DOI: 10.1038/s41598-021-98079-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/30/2021] [Indexed: 11/28/2022] Open
Abstract
Controlling the perpendicular magnetic anisotropy (PMA) in thin films has received considerable attention in recent years due to its technological importance. PMA based devices usually involve heavy-metal (oxide)/ferromagnetic-metal bilayers, where, thanks to interfacial spin-orbit coupling (SOC), the in-plane (IP) stability of the magnetisation is broken. Here we show that in V/MgO/Fe(001) epitaxial junctions with competing in-plane and out-of-plane (OOP) magnetic anisotropies, the SOC mediated interaction between a ferromagnet (FM) and a superconductor (SC) enhances the effective PMA below the superconducting transition. This produces a partial magnetisation reorientation without any applied field for all but the largest junctions, where the IP anisotropy is more robust; for the smallest junctions there is a reduction of the field required to induce a complete OOP transition (\documentclass[12pt]{minimal}
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\begin{document}$$H_\text {OOP}$$\end{document}HOOP) due to the stronger competition between the IP and OOP anisotropies. Our results suggest that the degree of effective PMA could be controlled by the junction lateral size in the presence of superconductivity and an applied electric field. We also discuss how the \documentclass[12pt]{minimal}
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\begin{document}$$H_\text {OOP}$$\end{document}HOOP field could be affected by the interaction between magnetic stray fields and superconducting vortices. Our experimental findings, supported by numerical modelling of the ferromagnet-superconductor interaction, open pathways to active control of magnetic anisotropy in the emerging dissipation-free superconducting spin electronics.
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Affiliation(s)
- César González-Ruano
- Departamento Física de la Materia Condensada C-III, Instituto Nicolás Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid, 28049, Spain
| | - Diego Caso
- Departamento Física de la Materia Condensada C-III, Instituto Nicolás Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid, 28049, Spain
| | - Lina G Johnsen
- Department of Physics, Center for Quantum Spintronics, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Coriolan Tiusan
- Department of Physics and Chemistry, Center of Superconductivity Spintronics and Surface Science C4S, Technical University of Cluj-Napoca, Cluj-Napoca, 400114, Romania.,Institut Jean Lamour, Nancy Universitè, 54506, Vandoeuvre-les-Nancy Cedex, France
| | - Michel Hehn
- Institut Jean Lamour, Nancy Universitè, 54506, Vandoeuvre-les-Nancy Cedex, France
| | - Niladri Banerjee
- Department of Physics, Loughborough University, Epinal Way, Loughborough, LE11 3TU, UK
| | - Jacob Linder
- Department of Physics, Center for Quantum Spintronics, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Farkhad G Aliev
- Departamento Física de la Materia Condensada C-III, Instituto Nicolás Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid, 28049, Spain.
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