TY  - JOUR
AU  - Savchenko, Andrii S.
AU  - Kuchkin, Vladyslav
AU  - Rybakov, Filipp N.
AU  - Kiselev, Nikolai
TI  - Magnetic bubbles with alternating chirality in domain walls
JO  - Frontiers in physics
VL  - 11
SN  - 2296-424X
CY  - Lausanne
PB  - Frontiers Media
M1  - FZJ-2023-02479
SP  - 1223609
PY  - 2023
AB  - In magnetic multilayers with perpendicular anisotropy, the competition of short-range and long-range interactions gives rise to the stability of cylindrical magnetic domains, also known as magnetic bubbles. The presence of Dzyaloshinsky-Moriya interaction induced by asymmetric interfaces between magnetic and nonmagnetic layers may lead to the formation of cylindrical bubble domains with Neel-type domain walls across the whole thickness of the multilayer. Such domain walls produce no contrast in Lorentz TEM under the normal incidence of the electron beam to the film. The latter is often used as an argument for the presence of Dzyaloshinskii-Moriya interaction in the system. Here we show that in magnetic multilayers, the absence of the Lorentz TEM contrast might also have another origin. In particular, in the absence of interfacial Dzyaloshinskii-Moriya interaction and weak interlayer exchange coupling, the magnetic bubbles might have Bloch-type domain walls of alternate chirality in adjacent layers. Such domain walls also do not produce magnetic contrast in Lorentz TEM at normal incidence of the electron beam. We show that, in the absence of interlayer exchange coupling, the magnetic bubble domains with the domain walls of fixed and alternate chirality have nearly identical energies and can coexist in the same range of magnetic fields. Using the geodesic nudged elastic band method, we prove that these states are separated by finite energy barriers. Furthermore, we demonstrate that magnetic multilayers with only dipolar coupling, besides the magnetic bubbles with nontrivial topology in all layers, can accommodate solutions with trivial topology within the internal layers.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001017882900001
DO  - DOI:10.3389/fphy.2023.1223609
UR  - https://juser.fz-juelich.de/record/1008688
ER  -