| 51. |
- Kumar, Ankit, et al.
(författare)
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Impact of the crystal orientation on spin-orbit torques in Fe/Pd bilayers
- 2020
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 53:35
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Tidskriftsartikel (refereegranskat)abstract
- Spin-orbit torques in ferromagnetic/non-magnetic heterostructures offer more energy-efficient means to realize spin-logic devices; however, their strengths are determined by the heterostructure interface. This work examines the impact of crystal orientation on the spin-orbit torque efficiency in different Fe/Pd bilayer systems. Results from spin torque ferromagnetic resonance measurements evidence that the damping-like torque efficiency is higher in epitaxial than in polycrystalline bilayer structures while the field-like torque is negligible in all bilayer structures. The strength of the damping-like torque decreases with deterioration of the bilayer epitaxial quality. The present finding provides fresh insight for the enhancement of spin-orbit torques in magnetic heterostructures.
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| 52. |
- Lebrun, Delphine, 1985-
(författare)
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Fabrication of inverse opal oxide structures for efficient light harvesting
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Artificial opals are self-assembled face centered cubic (fcc) structures of spherically shaped beads, which interesting applications as photonic band gap materials. Inverse opals are photonic crystals consisting of fcc paced voids of a low refractive index material imbedded in a high refractive index material. Such structures has been used to enhance the photocatalytic effect of different materials and motivates further studies to improve the deposition process of the opal templates and their inversion. We state the fabrication method to design and model metal oxide inverse opals. We have successfully created alumina and alumina-titania inverse opals. With the help of simulations, we engineered inverse opals with self-assembly and atomic layer deposition.
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| 53. |
- Liu, H., et al.
(författare)
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Enhanced optical mode coherence in exchange coupled soft magnetic multilayers
- 2022
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 131:21
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Tidskriftsartikel (refereegranskat)abstract
- We report on an all-optical investigation of coupled spin excitation modes in a series of magnetic trilayer structures. Using time-resolved magneto-optic Kerr effect (tr-MOKE) magnetometry, we observe multi-mode coherent spin excitations in Ni81Fe19/Ru/Co49Fe49V2 multi layers even though the tr-MOKE optical detection is sensitive only to the Co49Fe49V2 magnetization dynamics. Frequency shifts of the different modes indicate that the coupling between the Ni(81)Fe(19 a)nd Co49Fe49V2 layers varies from anti-ferromagnetic to ferromagnetic to uncoupled as the Ru spacer layer thickness is increased from 8 & Aring; to 200 & Aring;. The lifetime of the high frequency coherent oscillations in the Co49Fe49V2 layer increases by over 200%-300% even in the case of uncoupled Ni81Fe19 and Co49Fe49V2 layers with a 200 & Aring; thick Ru spacer. The results suggest an additional method to decrease the damping of high-moment alloys in layered magnetic nanostructures. Published under an exclusive license by AIP Publishing.
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| 54. |
- Maccaferri, Nicolò, Dr. 1988-, et al.
(författare)
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Nanoscale magnetophotonics
- 2020
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 127:8
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Tidskriftsartikel (refereegranskat)abstract
- This Perspective surveys the state-of-the-art and future prospects of science and technology employing nanoconfined light (nanophotonics and nanoplasmonics) in combination with magnetism. We denote this field broadly as nanoscale magnetophotonics. We include a general introduction to the field and describe the emerging magneto-optical effects in magnetoplasmonic and magnetophotonic nanostructures supporting localized and propagating plasmons. Special attention is given to magnetoplasmonic crystals with transverse magnetization and the associated nanophotonic non-reciprocal effects and to magneto-optical effects in periodic arrays of nanostructures. We also give an overview of the applications of these systems in biological and chemical sensing, as well as in light polarization and phase control. We further review the area of nonlinear magnetophotonics, the semiconductor spin-plasmonics, and the general principles and applications of opto-magnetism and nano-optical ultrafast control of magnetism and spintronics. © 2020 Author(s).
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| 55. |
- Magnfält, Daniel, et al.
(författare)
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Synthesis of tunable plasmonic metal-ceramic nanocomposite thin films by temporally modulated sputtered fluxes
- 2017
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 121:17
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Tidskriftsartikel (refereegranskat)abstract
- The scientific and technological interest for metal-dielectric nanocomposite thin films emanates from the excitation of localized surface plasmon resonances (LSPRs) on the metal component. The overall optical response of the nanocomposite is governed by the refractive index of the dielectric matrix and the properties of the metallic nanoparticles in terms of their bulk optical properties, size, and shape, and the inter-particle distance of separation. In order to tune the film morphology and optical properties, complex synthesis processes which include multiple steps-i. e., film deposition followed by post-deposition treatment by thermal or laser annealing-are commonly employed. In the present study, we demonstrate that the absorption resonances of Ag/AlOxNy nanocomposite films can be effectively tuned from green (similar to 2.4 eV) to violet (similar to 2.8 eV) using a single-step synthesis process that is based on modulating the arrival pattern of film forming species with sub-monolayer resolution, while keeping the amount of Ag in the films constant. Our data indicate that the optical response of the films is the result of LSPRs on isolated Ag nanoparticles that are seemingly shifted by dipolar interactions between neighboring particles. The synthesis strategy presented may be of relevance for enabling integration of plasmonic nanocomposite films on thermally sensitive substrates. Published by AIP Publishing.
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| 56. |
- Magnus, Fridrik, et al.
(författare)
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Giant magnetic domains in amorphous SmCo thin films
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:22, s. 224420-1-224420-5
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Tidskriftsartikel (refereegranskat)abstract
- The potential for tuning of magnetic properties and the exceptional uniformity are among the features that make amorphous magnetic materials attractive for technology. Here it is shown that the magnetization reversal in amorphous SmCo thin films takes place through the formation of giant magnetic domains, over a centimeter across. The domain structure is found to be dictated by the direction of the imprinted in-plane easy axis and the film boundaries. This is a consequence of the size of the anisotropy and the structural uniformity of the films, which also allows the movement of millimeter-long domain walls over distances of several millimeters. The results demonstrate the possibility of tailoring the magnetic domain structure in amorphous magnets over a wide range of length scales, up to centimeters. Moreover, they highlight an important consequence of the structural perfection of amorphous films.
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| 57. |
- Magnus, Fridrik, et al.
(författare)
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Magnetostrictive properties of amorphous SmCo thin films with imprinted anisotropy
- 2014
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:13, s. 134414-1-134414-6
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Tidskriftsartikel (refereegranskat)abstract
- We examine the magnetostriction in amorphous SmCo thin films with a composition in the range 4-27 at.% Sm. The magnetostriction increases significantly with increasing Sm content but is small compared to terbium-based ferromagnetic compounds, despite the large imprinted anisotropy. The magnetostriction and anisotropy both increase approximately linearly as the temperature is reduced. The magnetoelastic energy is found to be far smaller than the anisotropy energy so the magnetoelastic atomic displacements during growth cannot be the origin of the imprinted anisotropy. The anisotropy is only slightly altered by the application of large tensile stresses, indicating that the local strain fields involved in magnetostriction are not equivalent to the global strain produced by mechanical bending.
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| 58. |
- Magnus, Fridrik, et al.
(författare)
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Tunable giant magnetic anisotropy in amorphous SmCo thin films
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 102:16, s. 162402-
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Tidskriftsartikel (refereegranskat)abstract
- SmCo thin films have been grown by magnetron sputtering at room temperature with a composition of 2-35 at.% Sm. Films with 5 at.% or higher Sm are amorphous and smooth. A giant tunable uniaxial in-plane magnetic anisotropy is induced in the films which peaks in the composition range 11-22 at.% Sm. This cross-over behavior is not due to changes in the atomic moments but rather the local configuration changes. The excellent layer perfection combined with highly tunable magnetic properties make these films important for spintronics applications.
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| 59. |
- Martin, Nicolas, et al.
(författare)
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Low temperature electronic transport in sputter deposited a-IGZO films
- 2014
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Ingår i: Current applied physics. - : Elsevier BV. - 1567-1739 .- 1878-1675. ; 14:11, s. 1481-1485
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Tidskriftsartikel (refereegranskat)abstract
- We report on the electrical properties of a-IGZO thin films prepared by reactive sputtering. Without oxygen injection, dc resistivity measured at room temperature is rho(300K) = 1.22 x 10(-3) Omega m. The lowest resistivity rho(300K) = 4.86 x 10(-5) Omega m is obtained at a certain oxygen supply into the deposition process. Hall effect measurements of these films reveal a metallic-like behavior from mobility and carrier concentration vs. temperature in the range 15-300 K whereas films deposited without oxygen or for the highest oxygen flows behave as semiconductors. These enhanced electrical properties are connected to the oxygen vacancies and the local coordination structure around the In3+ cations.
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| 60. |
- 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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