| 1. |
- Borynskyi, V. Yu, et al.
(författare)
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Thermomagnetic transition in nanoscale synthetic antiferromagnets Py/NiCu/Py
- 2023
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - : AIP Publishing. - 1063-777X .- 1090-6517. ; 49:7, s. 863-869
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Tidskriftsartikel (refereegranskat)abstract
- Using the method of SQUID magnetometry, the features of the antiferromagnet-ferromagnet thermomagnetic transition in arrays of the nanosized disks of Py/NiCu/Py synthetic antiferromagnets (SAFs) have been investigated. The effective interlayer interaction in individual SAFs “ferromagnet/diluted ferromagnet/ferromagnet” (F2/f/F1) changes from high-temperature antiferromagnetic to low-temperature ferromagnetic upon the transition at the Curie temperature T C f of the interlayer f. Temperature dependence of the magnetic parameters of individual layers and their effect on the features of the thermomagnetic transition are determined. The observed properties are important for the development of temperature-controlled nanoscale SAFs and multilayer nanostructures based on them.
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| 2. |
- Borynskyi, V. Yu, et al.
(författare)
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Higher-order ferromagnetic resonances in periodic arrays of synthetic-antiferromagnet nanodisks
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:19
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Tidskriftsartikel (refereegranskat)abstract
- We investigate spin dynamics in nanodisk arrays of synthetic-antiferromagnets (SAF) made of Py/NiCu/Py trilayers, where the NiCu spacer undergoes a Curie transition at about 200 K. The observed ferromagnetic resonance spectra have three distinct resonance modes at room temperature, which are fully recreated in our micromagnetic simulations, showing also how the intra-SAF asymmetry can be used to create and control the higher-order resonances in the structure. Below the Curie temperature of the spacer, the system effectively transitions into a single-layer nanodisk array with only two resonance modes. Our results show how multilayering of nanoarrays can add tunable GHz functionality relevant for such rapidly developing fields as magnetic metamaterials, magnonic crystals, arrays of spin-torque oscillators, and neuromorphic junctions.
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| 3. |
- Polishchuk, Dmytr, et al.
(författare)
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Isotropic FMR frequency enhancement in thin Py/FeMn bilayers under strong magnetic proximity effect
- 2021
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 54:30
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Tidskriftsartikel (refereegranskat)abstract
- Exchange biasing in ferromagnet/antiferromagnet bilayers is known to enhance the material's ferromagnetic resonance frequency and make it strongly angle dependent due to the unidirectional anisotropy induced at the interface. We observe a ten-fold enhancement in frequency and angle-independent ferromagnetic resonance in bilayers of Py/FeMn with ultrathin FeMn, accompanied by a significantly enhanced magnetic moment. The observed isotropic frequency enhancement is consistent with rotatable rather than unidirectional magnetic anisotropy and the induced magnetic moment links this anisotropy with the ferromagnet-proximity effect. The estimated effective anisotropy field acting on the proximity-induced moment in ultrathin FeMn can be as high as 0.5 T at room temperature. Our results show the potential of the ferromagnetic proximity effect combined with the inherent exchange anisotropy in antiferromagnets for high-speed spintronic applications.
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| 4. |
- Polishchuk, Dmytr, et al.
(författare)
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Spin-current dissipation in a thin-film bilayer ferromagnet/antiferromagnet
- 2020
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - : American Institute of Physics (AIP). - 1063-777X .- 1090-6517. ; 46:8, s. 813-819
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Tidskriftsartikel (refereegranskat)abstract
- Ferromagnetic resonance in multilayer metal nanostructures containing an antiferromagnetic layer of variable thickness is studied. The contribution to the linewidth of the ferromagnetic resonance that is caused by spin-pumping current dissipation in an exchange-coupled antiferromagnetic/ferromagnetic bilayer is determined. The dissipative processes that occur in the bulk of the antiferromagnet and at the interface between the antiferromagnet (Fe50Mn50) and the ferromagnet (permalloy, Ni81Fe19) are distinguished. The details of how the dissipation transforms when the antiferromagnet Neel vector deviates from the direction of the exchange-pinning field are determined. The proposed method is effective for studying spin scattering in individual layers and at interlayer interfaces in complex magnetic systems.
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