Generation of highly anisotropic physical properties in ferromagnetic thin films controlled by their differently oriented nano-sheets
Fecha
2024Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión aceptada / Onetsi den bertsioa
Identificador del proyecto
Impacto
|
10.1063/9.0000813
Resumen
We fabricated ferromagnetic nano-crystalline thin films of Co, Fe, Co–Fe and Co-rich and Fe-rich, Co–MT and Fe–MT (MT = transition
metal), constituted by nano-sheets with a controlled slant. Visualization of these nano-sheets by Scanning Tunneling Microscopy and HighResolution Transmission Electron Microscopy (HRTEM) showed typically tilt angles ≈56○ with respect to the substrate plane, and nano ...
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We fabricated ferromagnetic nano-crystalline thin films of Co, Fe, Co–Fe and Co-rich and Fe-rich, Co–MT and Fe–MT (MT = transition
metal), constituted by nano-sheets with a controlled slant. Visualization of these nano-sheets by Scanning Tunneling Microscopy and HighResolution Transmission Electron Microscopy (HRTEM) showed typically tilt angles ≈56○ with respect to the substrate plane, and nano-sheets
≈3.0–4.0 nm thick, ≈30–100 nm wide, and ≈200–300 nm long, with an inter-sheet distance of ≈0.9–1.2 nm, depending on their constitutive
elements. Induced by this nano-morphology, these films exhibited large uniaxial magnetic anisotropy in the plane, the easy direction of
magnetization being parallel to the longitudinal direction of the nano-sheets. In the as-grown films, typical values of the anisotropy field
were between Hk ≈ 48 and 110 kA/m depending on composition. The changes in the nano-morphology caused by thermal treatments, and
hence in the anisotropic properties, were also visualized by HRTEM, including chemical analysis at the nano-scale. Some films retained their
nano-sheet morphology and increased their anisotropies by up to three times after being heated to at least 500 ○C: for example, the thermal
treatments produced crystallization processes and the growth of CoV and CoFe magnetic phases, maintaining the nano-sheet morphology.
In contrast, other annealed films, Co, Fe, CoZn, CoCu. . . lost their nano-sheet morphology and hence their anisotropies. This work opens a
path of study for these new magnetically anisotropic materials, particularly with respect to the nano-morphological and structural changes
related to the increase in magnetic anisotropy. [--]
Materias
Ferromagnetic thin films,
Nano-sheets,
Uniaxial magnetic anisotropy
Editor
American Institute of Physics
Publicado en
AIP Advances 14(2), 025237, (2024)
Departamento
Universidad Pública de Navarra. Departamento de Ciencias /
Nafarroako Unibertsitate Publikoa. Zientziak Saila /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute for Advanced Materials and Mathematics - INAMAT2
Versión del editor
Entidades Financiadoras
C. F., J. V., and V. M. acknowledge the partial financial support of the Universidad Pública de Navarra to attend the 68th Annual Conference on Magnetism and Magnetism Materials held in Dallas (TX, USA) to present the invited talk on which this work is based. C. M. and M. R. I. acknowledge the financial support from the Spanish Ministerio de Economía y Competitividad, Project No. MAT2017–82970-C1 and C2-R and from the Aragón Regional, project E26.