| 1. |
- Melander, Emil, et al.
(författare)
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Influence of the magnetic field on the plasmonic properties of transparent Ni anti-dot arrays
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:6, s. 063107-
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Tidskriftsartikel (refereegranskat)abstract
- Extraordinary optical transmission is observed due to the excitation of surface plasmon polaritons in 2-dimensional hexagonal anti-dot patterns of pure Ni thin films, grown on sapphire substrates. A strong enhancement of the polar Kerr rotation is recorded at the surface plasmon related transmission maximum. Angular resolved reflectivity measurements under an applied field reveal an enhancement and a shift of the normalized reflectivity difference upon reversal of the magnetic saturation (transverse magneto-optical Kerr effect-TMOKE). The change of the TMOKE signal clearly shows the magnetic field modulation of the dispersion relation of SPPs launched in a 2D patterned ferromagnetic Ni film. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4742931]
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| 2. |
- Moubah, Reda, et al.
(författare)
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Tailoring magnetism at the nanometer scale in SmCo5 amorphous films
- 2013
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 25:41, s. 416004-
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Tidskriftsartikel (refereegranskat)abstract
- The thickness dependence of magnetic properties has been studied in SmCo5 amorphous films with imprinted in-plane anisotropy for thicknesses ranging down to the nanometer scale (2.5-100 nm). The field induced in-plane magnetic anisotropy decreases considerably when the film thickness is below 20 nm. Analysis of the magnetic anisotropy energy shows that the decrease of the induced in-plane anisotropy is accompanied by the development of an out-of-plane interface anisotropy. Two different regimes for the coercivity (H-c) change are found: below 3.75 nm, the H-c decreases continuously with decrease of the film thickness, whereas at above 3.75 nm, the H-c decreases with increase of the film thickness. This change in Hc can be understood by considering the decrease of the short range chemical order for the thinnest films (<3.75 nm) and the relative decrease of the interface contribution with increasing film thickness. The changes in anisotropy have a profound influence on the domain structure, in which the angle of the zigzag domain boundaries decreases with the inverse thickness of the layers.
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| 3. |
- Östman, Erik, et al.
(författare)
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Hysteresis-free switching between vortex and collinear magnetic states
- 2014
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 16, s. 053002-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a lossless switching between vortex and collinear magnetic states in circular FePd disks arranged in a square lattice. Above a bifurcation temperature (Te) we show that thermal fluctuations are enough to facilitate flipping between the two distinctly different magnetic states. We find that the temperature dependence of the vortex annihilation and nucleation fields can be described by a simple power law relating them to the saturation magnetization.
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| 4. |
- Östman, Erik, et al.
(författare)
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Interaction modifiers in artificial spin ices
- 2018
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Ingår i: Nature Physics. - : NATURE PUBLISHING GROUP. - 1745-2473 .- 1745-2481. ; 14:4, s. 375-379
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Tidskriftsartikel (refereegranskat)abstract
- The modification of geometry and interactions in two-dimensional magnetic nanosystems has enabled a range of studies addressing the magnetic order(1-6), collective low-energy dynamics(7,8) and emergent magnetic properties(5,9,10) in, for example, artificial spin-ice structures. The common denominator of all these investigations is the use of Ising-like mesospins as building blocks, in the form of elongated magnetic islands. Here, we introduce a new approach: single interaction modifiers, using slave mesospins in the form of discs, within which the mesospin is free to rotate in the disc plane(11). We show that by placing these on the vertices of square artificial spin-ice arrays and varying their diameter, it is possible to tailor the strength and the ratio of the interaction energies. We demonstrate the existence of degenerate ice-rule-obeying states in square artificial spin-ice structures, enabling the exploration of thermal dynamics in a spin-liquid manifold. Furthermore, we even observe the emergence of flux lattices on larger length scales, when the energy landscape of the vertices is reversed. The work highlights the potential of a design strategy for two-dimensional magnetic nano-architectures, through which mixed dimensionality of mesospins can be used to promote thermally emergent mesoscale magnetic states.
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| 5. |
- Östman, Erik, et al.
(författare)
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Ising-like behaviour of mesoscopic magnetic chains
- 2018
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 30:36
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an experimental realization of the short range magnetic order in a one-dimensional Ising chain using fabricated mesospins. We confirm an excellent agreement between the experimental findings and simulations obtained using the original Ising model. In particular, we are able to show that the thermal behaviour of the mesoscopic Ising chain dominates over the thermal behaviour of the individual mesospins themselves, confirming that fabricated mesospins can be viewed as artificial magnetic atoms.
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