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Bersweiler, M.*; 大場 洋次郎; Sinaga, E. P.*; Peral, I.*; Titov, I.*; Adams, M. P.*; Rai, V.*; Metlov, K. L.*; Michels, A.*
Physical Review B, 108(9), p.094434_1 - 094434_7, 2023/09
被引用回数:4 パーセンタイル:68.65(Materials Science, Multidisciplinary)Magnetic nanostructure in an isotropic Nd-Fe-B bulk magnet was investigated using small-angle neutron scattering. The two-dimensional scattering patterns show the so-called spike anisotropy, which points the presence of a strong magnetodipolar interaction within the sample. The field-dependence of the scattering intensity is explained by a vortex-like flux closure structure. This suggests that magnetic vortices form pairs.
Bersweiler, M.*; 佐藤 宏和*; 足立 望*; 戸高 義一*; Peral, I.*; Kohlbrecher, J.*; Zaporozhets, V. D.*; Metlov, K. L.*; Michels, A.*; 大場 洋次郎
IUCrJ, 10(4), p.411 - 419, 2023/07
被引用回数:2 パーセンタイル:60.51(Chemistry, Multidisciplinary)Magnetic microstructures in severely deformed iron produced via high-pressure torsion (HPT) straining have been investigated using small-angle neutron scattering. The results reveal that nonneglibible third-order scattering contribution in the inhomogeneities amplitude of magnetization is induced via HPT straining and the contribution becomes small with subsequent annealing. The contribution has negative values, which suggest that the inhomogeneity of the magnetic anisotropy enhanced via HPT is a possible origin of the third-order contribution.
Zaporozhets, V. D.*; 大場 洋次郎; Michels, A.*; Metlov, K. L.*
Journal of Applied Crystallography, 55(3), p.592 - 600, 2022/06
被引用回数:8 パーセンタイル:86.12(Chemistry, Multidisciplinary)Micromagnetic theory well explains the magnetic small-angle neutron scattering (SANS) data of bulk ferromagnets. However, only the samples having random magnetic anisotropy are mainly handled. In this study, the micromagnetic SANS theory is extended to allow to analyze uniaxial magnetic anisotropy. Micromagnetic response functions for SANS are computed analytically for several practical arrangements of anisotropy and external magnetic field orientations. This theory agrees well with the experimental SANS data of a practical soft magnet and plastically-deformed Ni and successfully provides the uniaxial anisotropy quality factors.
大場 洋次郎; Bersweiler, M.*; Titov, I.*; 足立 望*; 戸高 義一*; Gilbert, E. P.*; Steinke, N.-J.*; Metlov, K. L.*; Michels, A.*
Physical Review Materials (Internet), 5(8), p.084410_1 - 084410_9, 2021/08
被引用回数:3 パーセンタイル:16.67(Materials Science, Multidisciplinary)We found that nanosized spin misalignments in pure nickel processed via high-pressure torsion straining persist up to the magnetic field 4 T using small-angle neutron scattering (SANS). The spin-misalignment scattering patterns are elongated perpendicular to the applied magnetic field and different from the conventional micromagnetic SANS theory based on the second order contribution in spin misalignment amplitude. This means that the high-pressure torsion straining makes higher-order effects in the micromagnetic SANS cross sections observable. This results will fuel the further development of the micromagnetic SANS theory.