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Kanistras N, Scheuer L, Anyfantis DI, Barnasas A, Torosyan G, Beigang R, Crisan O, Poulopoulos P, Papaioannou ET. Magnetic Properties and THz Emission from Co/CoO/Pt and Ni/NiO/Pt Trilayers. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:215. [PMID: 38276733 PMCID: PMC11154404 DOI: 10.3390/nano14020215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/02/2024] [Accepted: 01/12/2024] [Indexed: 01/27/2024]
Abstract
THz radiation emitted by ferromagnetic/non-magnetic bilayers is a new emergent field in ultra-fast spin physics phenomena with a lot of potential for technological applications in the terahertz (THz) region of the electromagnetic spectrum. The role of antiferromagnetic layers in the THz emission process is being heavily investigated at the moment. In this work, we fabricate trilayers in the form of Co/CoO/Pt and Ni/NiO/Pt with the aim of studying the magnetic properties and probing the role of very thin antiferromagnetic interlayers like NiO and CoO in transporting ultrafast spin current. First, we reveal the static magnetic properties of the samples by using temperature-dependent Squid magnetometry and then we quantify the dynamic properties with the help of ferromagnetic resonance spectroscopy. We show magnetization reversal that has large exchange bias values and we extract enhanced damping values for the trilayers. THz time-domain spectroscopy examines the influence of the antiferromagnetic interlayer in the THz emission, showing that the NiO interlayer in particular is able to transport spin current.
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Affiliation(s)
- Nikolaos Kanistras
- Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann Platz 3, 06120 Halle, Germany;
| | - Laura Scheuer
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany; (L.S.); (R.B.)
| | - Dimitrios I. Anyfantis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece; (D.I.A.); (A.B.); (P.P.)
| | - Alexandros Barnasas
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece; (D.I.A.); (A.B.); (P.P.)
| | - Garik Torosyan
- Photonik Center Kaiserslautern, 67663 Kaiserslautern, Germany;
| | - René Beigang
- Fachbereich Physik and Landesforschungszentrum OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663 Kaiserslautern, Germany; (L.S.); (R.B.)
| | - Ovidiu Crisan
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania;
| | - Panagiotis Poulopoulos
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece; (D.I.A.); (A.B.); (P.P.)
| | - Evangelos Th. Papaioannou
- Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann Platz 3, 06120 Halle, Germany;
- National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania;
- Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Anyfantis DI, Ballani C, Kanistras N, Barnasas A, Tsiaoussis I, Schmidt G, Papaioannou ET, Poulopoulos P. Magnetic Anisotropies and Exchange Bias of Co/CoO Multilayers with Intermediate Ultrathin Pt Layers. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1378. [PMID: 36837008 PMCID: PMC9963626 DOI: 10.3390/ma16041378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/30/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Co/CoO multilayers are fabricated by means of radio-frequency magnetron sputtering. For the formation of each multilayer period, a Co layer is initially produced followed by natural oxidation. Platinum is used not only as buffer and capping layers, but also in the form of intermediate ultrathin layers to enhance perpendicular magnetic anisotropy. Three samples are compared with respect to the magnetic anisotropies and exchange bias between 4-300 K based on superconducting quantum interference device magnetometry measurements. Two of the multilayers are identical Co/CoO/Pt ones; one of them, however, is grown on a Co/Pt "magnetic substrate" to induce perpendicular magnetic anisotropy via exchange coupling through an ultrathin Pt intermediate layer. The third multilayer is of the form Co/CoO/Co/Pt. The use of a "magnetic substrate" results in the observation of loops with large remanence when the field applies perpendicular to the film plane. The CoO/Co interfaces lead to a significant exchange bias at low temperatures after field cooling. The largest exchange bias was observed in the film with double Co/CoO/Co interfaces. Consequently, significant perpendicular anisotropy coexists with large exchange bias, especially at low temperatures. Such samples can be potentially useful for applications related to spintronics and magnetic storage.
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Affiliation(s)
- Dimitrios I. Anyfantis
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Camillo Ballani
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Nikos Kanistras
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Alexandros Barnasas
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
| | - Ioannis Tsiaoussis
- Department of Physics, School of Natural Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Georg Schmidt
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
- Interdisziplinäres Zentrum für Materialwissenschaften, Nanotechnikum Weinberg, Martin-Luther University Halle-Wittenberg, 06120 Halle, Germany
| | - Evangelos Th. Papaioannou
- Institut für Physik, Martin-Luther Universität Halle Wittenberg, Von-Danckelmann-Platz 3, 06120 Halle, Germany
| | - Panagiotis Poulopoulos
- Department of Materials Science, School of Natural Sciences, University of Patras, 26504 Patras, Greece
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