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Microstructural-defect-induced Dzyaloshinskii-Moriya interaction

Abstract: The antisymmetric Dzyaloshinskii?Moriya interaction (DMI) plays a decisive role for the stabilization and control of chirality of skyrmion textures in various magnetic systems exhibiting a noncentrosymmetric crystal structure. A less studied aspect of the DMI is that this interaction is believed to be operative in the vicinity of lattice imperfections in crystalline magnetic materials, due to the local structural inversion symmetry breaking. If this scenario leads to an effect of sizable magnitude, it implies that the DMI introduces chirality into a very large class of magnetic materials?defect-rich systems such as polycrystalline magnets. Here, we show experimentally that the microstructural-defect-induced DMI gives rise to a polarization-dependent asymmetric term in the small-angle neutron scattering (SANS) cross section of polycrystalline ferromagnets with a centrosymmetric crystal structure. The results are supported by theoretical predictions using the continuum theory of micromagnetics. This effect, conjectured already by Arrott in 1963, is demonstrated for nanocrystalline terbium and holmium (with a large grain-boundary density), and for mechanically deformed microcrystalline cobalt (with a large dislocation density). Analysis of the scattering asymmetry allows one to determine the defect-induced DMI constant, D = 0.45 ± 0.07 mJ / m 2 for Tb at 100 K . Our study proves the generic relevance of the DMI for the magnetic microstructure of defect-rich ferromagnets with vanishing intrinsic DMI. Polarized SANS is decisive for disclosing the signature of the defect-induced DMI, which is related to the unique dependence of the polarized SANS cross section on the chiral interactions. The findings open up the way to study defect-induced skyrmionic magnetization textures in disordered materials.

Otras publicaciones de la misma revista o congreso con autores/as de la Universidad de Cantabria

 Autoría: Michels A., Mettus D., Titov I., Malyeyev A., Bersweiler M., Bender P., Peral I., Birringer R., Quan Y., Hautle P., Kohlbrecher J., Honecker D., Fernández J., Barquín L., Metlov K.,

 Fuente: Phys. Rev. B, 99, 1, 014416 (2019)

Editorial: American Physical Society

 Fecha de publicación: 01/01/2019

Nº de páginas: 8

Tipo de publicación: Artículo de Revista

DOI: 10.1103/PhysRevB.99.014416

ISSN: 1098-0121,1550-235X,2469-9950,2469-9969

Url de la publicación: https://doi.org/10.1103/PhysRevB.99.014416

Autores/as

MICHELS, ANDREAS

METTUS, DENIS

TITOV, IVAN

MALYEYEV, ARTEM

BERSWEILER, MATHIAS

PHILIPP FLORIAN BENDER

PERAL, INMA

BIRRINGER, RAINER

QUAN, YIFAN

HAUTLE, PATRICK

KOHLBRECHER, JOACHIM

HONECKER, DIRK

METLOV, KONSTANTIN L.