References of "Michels, Andreas 50002669"
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See detailUniaxial polarization analysis of bulk ferromagnets: theory and first experimental results
Malyeyev, Artem UL; Titov, Ivan UL; Dewhurst, Charles et al

in Journal of Applied Crystallography (2022), 55

Based on Brown’s static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into ... [more ▼]

Based on Brown’s static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into account the isotropic exchange interaction, the antisymmetric Dzyaloshinskii–Moriya interaction, magnetic anisotropy, the dipole–dipole interaction, as well as the effect of an applied magnetic field. In the high-field limit, the solutions for the magnetization Fourier components are used to obtain closed-form results for the spinpolarized SANS (small-angle neutron scattering) cross sections and the ensuing polarization. The theoretical expressions are compared with experimental data on a soft magnetic nanocrystalline alloy. The micromagnetic SANS theory provides a general framework for polarized real-space neutron methods, and it may open up a new avenue for magnetic neutron data analysis on magnetic microstructures. [less ▲]

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See detailUsing small-angle scattering to guide functional magnetic nanoparticle design
Honecker, Dirk; Bersweiler, Mathias UL; Erokhin, Sergey et al

in Nanoscale Advances (2022), 4

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See detailSmall-angle neutron scattering by spatially inhomogeneous ferromagnets with a nonzero average uniaxial anisotropy
Zaporozhets, V. D.; Oba, Y.; Michels, Andreas UL et al

in Journal of Applied Crystallography (2022), 55

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See detailMagnetic order and disorder environments in superantiferromagnetic NdCu2 nanoparticles
Jefremovas, E.M.; Svedlindh, P.; Damay, F. et al

in Scientific Reports (2022), 12

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See detailMuMag2022: a software tool for analyzing magnetic field dependent unpolarized small-angle neutron scattering data of bulk ferromagnets
Adams, Michael Philipp UL; Bersweiler, Mathias UL; Jefremovas, Elizabeth Martín et al

in Journal of Applied Crystallography (2022), 55

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See detailQuantum Skyrmion Lattices in Heisenberg Ferromagnets
Haller, Andreas UL; Groenendijk, Solofo; Habibi, Alireza et al

E-print/Working paper (2021)

Skyrmions are topological magnetic textures which can arise in non-centrosymmetric ferromagnetic materials. In most systems experimentally investigated to date, skyrmions emerge as classical objects ... [more ▼]

Skyrmions are topological magnetic textures which can arise in non-centrosymmetric ferromagnetic materials. In most systems experimentally investigated to date, skyrmions emerge as classical objects. However, the discovery of skyrmions with nanometer length scales has sparked interest in their quantum properties. Quantum corrections to the classical magnetic textures have already been considered in the semiclassical regime. Here, we go beyond this limit by investigating quantum skyrmions in the deep quantum regime. We use density matrix renormalization group techniques to study two-dimensional spin-1/2 Heisenberg ferromagnets with Dzyaloshinskii-Moriya interactions and discover a broad region in the zero temperature phase diagram which hosts quantum skyrmion lattice ground states. We argue that this novel quantum skyrmion phase can be detected experimentally in the magnetization profile via local magnetic polarization measurements as well as in the spin structure factor measurable via neutron scattering experiments. Finally, we explore the resulting quantum skyrmion state, analyze its real space polarization profile and show that it is a non-classical state featuring entanglement between quasiparticle and environment mainly localized near the boundary spins of the skyrmion. [less ▲]

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See detailRole of higher-order effects in spin-misalignment small-angle neutron scattering of high-pressure torsion nickel
Oba, Yojiro; Bersweiler, Mathias UL; Titov, Ivan et al

in Physical Review Materials (2021), 5

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See detailRevealing defect-induced spin disorder in nanocrystalline Ni
Bersweiler, Mathias UL; Sinaga, Evelyn Pratami UL; Peral Alonso, Inmaculada UL et al

in Physical Review Materials (2021), 5(4), 044409

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See detailNeutron study of magnetic correlations in rare-earth-free Mn-Bi magnets
Malyeyev, Artem UL; Titov, Ivan; Bender, Philipp et al

in Physical Review Materials (2021), 5

We report the results of an unpolarized small-angle neutron scattering (SANS) study on Mn-Bi-based rare-earth-free permanent magnets. The magnetic SANS cross section is dominated by long-wavelength ... [more ▼]

We report the results of an unpolarized small-angle neutron scattering (SANS) study on Mn-Bi-based rare-earth-free permanent magnets. The magnetic SANS cross section is dominated by long-wavelength transversal magnetization fluctuations and has been analyzed in terms of the Guinier-Porod model and the distance distribution function. This provides the radius of gyration which, in the remanent state, ranges between about $220-240 \, \mathrm{nm}$ for the three different alloy compositions investigated. Moreover, computation of the distance distribution function in conjunction with results for the so-called $s$-parameter obtained from the Guinier-Porod model indicate that the magnetic scattering of a Mn$_{45}$Bi$_{55}$ sample has its origin in slightly shape-anisotropic structures. [less ▲]

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See detailChemical vapor deposition of CoFe2O4 micropillar arrays with enhanced magnetic properties
Aspe, B.; Malyeyev, Artem UL; Vakilinejad, A. et al

in Journal of Alloys and Compounds (2021), 890

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See detailLow-Temperature Growth of AlN Films on Magnetostrictive Foils for High-Magnetoelectric-Response Thin-Film Composites
Nguyen, T.; Fleming, Y.; Bender, P. et al

in ACS Applied Materials and Interfaces (2021), 13

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See detailObservation of surface magnons and crystalline electric field shifts in superantiferromagnetic NdCu2 nanoparticles
Jefremovas, E. M.; de la Fuente Rodríguez, M.; Damay, F. et al

in Physical Review. B, Condensed Matter (2021), 104

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See detailUnraveling Nanostructured Spin Textures in Bulk Magnets
Bender, Philipp Florian UL; Leliaert, Jonathan; Bersweiler, Mathias UL et al

in Small Science (2021), 1(1), 2000003

One of the key challenges in magnetism remains the determination of the nanoscopic magnetization profile within the volume of thick samples, such as permanent ferromagnets. Thanks to the large penetration ... [more ▼]

One of the key challenges in magnetism remains the determination of the nanoscopic magnetization profile within the volume of thick samples, such as permanent ferromagnets. Thanks to the large penetration depth of neutrons, magnetic small-angle neutron scattering (SANS) is a powerful technique to characterize bulk samples. The major challenge regarding magnetic SANS is accessing the real-space magnetization vector field from the reciprocal scattering data. In this letter, a fast iterative algorithm is introduced that allows one to extract the underlying two-dimensional magnetic correlation functions from the scattering patterns. This approach is used here to analyze the magnetic microstructure of Nanoperm, a nanocrystalline alloy which is widely used in power electronics due to its extraordinary soft magnetic properties. It can be shown that the computed correlation functions clearly reflect the projection of the three-dimensional magnetization vector field onto the detector plane, which demonstrates that the used methodology can be applied to probe directly spin-textures within bulk samples with nanometer-resolution. This article is protected by copyright. All rights reserved. [less ▲]

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See detailMagnetic Small-Angle Neutron Scattering. A Probe for Mesoscale Magnetism Analysis
Michels, Andreas UL

Book published by Oxford University Press (2021)

Detailed reference viewed: 108 (11 UL)
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See detailToward Understanding Complex Spin Textures in Nanoparticles by Magnetic Neutron Scattering
G. Vivas, Laura; Yanes, Rocio; Berkov, Dmitry et al

in Physical Review Letters (2020), 125

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See detailMagnetic correlations in polycrystalline Tb0.15Co0.85
Bersweiler, Mathias UL; Bender, Philipp Florian UL; Peral Alonso, Inmaculada UL et al

in Journal of Physics: D Applied Physics (2020), 53

Detailed reference viewed: 137 (21 UL)