Exotic Topological Magnetic States in Thin Co/Pd Ferromagnetic Films

• Published in: Annalen der Physik Vol. 536; no. 7
• Main Authors: Dorokhin, Mikhail V., Ved, Mikhail V., Kalentyeva, Irina L., Demina, Polina B., Zdoroveyshchev, Anton V., Zdoroveyshchev, Daniil A., Kudrin, Alexey V., Temiryazeva, Marina P., Temiryazev, Alexei G., Tatarskiy, Dmitry A., Trushin, Vladimir N., Orlova, Anastasia N., Kriukov, Ruslan N., Zubkov, Sergey Yu, Sadovnikov, Alexandr V.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.07.2024
• Subjects: Bilayers; Cobalt; Domain walls; Electron beams; Electron microscopy; Electrons; Ferromagnetic films; Ferromagnetic materials; Heavy metals; Hypothetical particles; magnetic films and multilayers; Magnetic force microscopy; Magnetic properties; Magnetic recording; micromagnetic structure; Microscopy; Multilayers; Palladium; Particle theory; skyrmioniums; skyrmions; Thickness; Thin films; Tooling; Topology
• ISSN: 0003-3804; 1521-3889
• DOI: 10.1002/andp.202300480

Thin ferromagnet/heavy metal multilayer films are considered as prospective media for a magnetic recording and Co/Pd films are a good example of such materials. In this work, the magnetic properties and micromagnetic structure of Co/Pd multilayer films are studied with different bilayer thicknesses ([Co(0.3 × t nm)/Pd(0.5 × t nm)]10), but with the same ratio Co versus Pd. Transmission electron microscope and X‐ray diffraction studies allow authors to suppose that the investigated films are highly mixed alloys. Magnetic force microscopy and Lorentz transmission electron microscopy showed the presence of various micromagnetic features in the films. Along with skyrmions that are well‐known magnetic topological artifacts some new features are revealed, which are interpreted as 360° domain walls, skyrmioniums and the combination of the above two. It is found that the type and density of micromagnetic features strongly depend on the bilayer thickness parameter (t). The effect is associated with the peculiarities of interfacial magnetic interactions in the samples with highly mixed interfaces. The tooling coefficient represents a useful tool of the electron beam evaporation technique enabling wide manipulation of micromagnetic particles, in particular, skyrmioniums that are currently considered a prospective media for current driven magnetic recording. The magnetic properties and micromagnetic structure of Co/Pd multilayer films with different bilayer thicknesses, but with the same ratio Co versus Pd are studied. A number of micromagnetic features in the films are revealed, such as skyrmions, 360° domain walls, skyrmioniums and the combination of them.