Results 1-13 of 13.
((uid:50009389))

Bookmark and Share    
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 53 (5 UL)
Full Text
Peer Reviewed
See detailMagnetic Guinier law
Michels, Andreas UL; Malyeyev, Artem UL; Titov, Ivan UL et al

in IUCrJ (2020), 7

Small-angle scattering of x-rays and neutrons is a routine method for the determination of nanoparticle sizes. The so-called Guinier law represents the low-q approximation for the small-angle scattering ... [more ▼]

Small-angle scattering of x-rays and neutrons is a routine method for the determination of nanoparticle sizes. The so-called Guinier law represents the low-q approximation for the small-angle scattering curve from an assembly of particles. The Guinier law has originally been derived for nonmagnetic particle-matrix-type systems, and it is successfully employed for the estimation of particle sizes in various scientific domains (e.g., soft matter physics, biology, colloidal chemistry, materials science). An important prerequisite for it to apply is the presence of a discontinuous interface separating particles and matrix. Here, we introduce the Guinier law for the case of magnetic small-angle neutron scattering (SANS) and experimentally demonstrate its applicability for the example of nanocrystalline cobalt. It is well- known that the magnetic microstructure of nanocrystalline ferromagnets is highly nonuniform on the nanometer length scale and characterized by a spectrum of continuously varying long-wavelength magnetization fluctuations, i.e., these systems do not manifest sharp interfaces in their magnetization profile. The magnetic Guinier radius depends on the applied magnetic field, on the magnetic interactions (exchange, magnetostatics), and on the magnetic anisotropy-field radius, which characterizes the size over which the magnetic anisotropy field is coherently aligned into the same direction. In contrast to the nonmagnetic conventional Guinier law, the magnetic version can be applied to fully dense random-anisotropy-type ferromagnets. [less ▲]

Detailed reference viewed: 84 (17 UL)
Full Text
Peer Reviewed
See detailAnisometric mesoscale nuclear and magnetic texture in sintered Nd-Fe-B magnets
Titov, Ivan UL; Honecker, Dirk UL; Mettus, Denis et al

in Physical Review Materials (2020), 4

Detailed reference viewed: 91 (7 UL)
Full Text
Peer Reviewed
See detailEffect of grain-boundary diffusion process on the geometry of the grain microstructure of Nd−Fe−B nanocrystalline magnets
Titov, Ivan UL; Barbieri, Massimiliano; Bender, Philipp Florian UL et al

in Physical Review Materials (2019), 3(084410),

Detailed reference viewed: 102 (7 UL)
Full Text
Peer Reviewed
See detailMicrostructural-defect-induced Dzyaloshinskii-Moriya interaction
Michels, Andreas UL; Mettus, Denis; Titov, Ivan UL et al

in Physical Review. B, Condensed Matter (2019), 99

Detailed reference viewed: 185 (26 UL)
Full Text
Peer Reviewed
See detailEvidence for the formation of nanoprecipitates with magnetically disordered regions in bulk Ni50Mn45In5 Heusler alloys
Benacchio, G.; Titov, Ivan UL; Malyeyev, Artem UL et al

in Physical Review. B, Condensed Matter and Materials Physics (2019), 99

Detailed reference viewed: 204 (24 UL)
Full Text
Peer Reviewed
See detailComposition and phases in laser welded Al-Cu joints by synchrotron x-ray microdiffraction
Schmalen, Pascal Guy UL; Plapper, Peter UL; Peral Alonso, Inmaculada UL et al

in Proceedings of 10th CIRP Conference on Photonic Technologies [LANE 2018] (2018)

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical ... [more ▼]

This paper presents the characterization of the intermetallic phases of laser-welded Al-Cu joints by synchrotron trough-the-substrate microdiffraction combined with SEM/EDX and etched/non-etched optical micrographs. Transmission microdiffraction offers the spatial resolution and beam flux necessary to study the intermetallic phases, which in conjunction with the excellent contrast of etched micrographs, rendered possible the phase identification. It was found that the major phases are Al2Cu (θ), Al4Cu9 (γ1) and AlCu (η2) were formed. The Al3Cu4 (ζ1) and δ phases where formed in less amount and found to be the primary cause for cracks inside the weld seam and therefore for the failure of the joint. [less ▲]

Detailed reference viewed: 153 (6 UL)
Peer Reviewed
See detailSpin structure of Nd-Fe-B-based textured nanocomposites:role of interface chemistry
Titov, Ivan UL; Michels, Andreas UL

Scientific Conference (2017, July 02)

Detailed reference viewed: 80 (4 UL)
Full Text
Peer Reviewed
See detailSmall-angle neutron scattering study of coercivity enhancement in grain-boundary-diffused Nd-Fe-B sintered magnets
Périgo, E.A.; Titov, Ivan UL; Weber, R. et al

in Journal of Alloys and Compounds (2016), 677

Detailed reference viewed: 141 (2 UL)