Nanostructure-induced L 1 0 -ordering of twinned single-crystals in CoPt ferromagnetic nanowires.

Autor: Toyama R; Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan majima@msl.titech.ac.jp., Kawachi S; Materials Research Center for Element Strategy, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan.; Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan.; Graduate School of Science, University of Hyogo Kamigori Hyogo 678-1297 Japan., Yamaura JI; Materials Research Center for Element Strategy, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan.; Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan., Fujita T; School of Environmental Science and Engineering, Kochi University of Technology Kami Kochi 782-8502 Japan., Murakami Y; Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK) Tsukuba Ibaraki 305-0801 Japan., Hosono H; Materials Research Center for Element Strategy, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan., Majima Y; Laboratory for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan majima@msl.titech.ac.jp.; Materials Research Center for Element Strategy, Tokyo Institute of Technology Yokohama Kanagawa 226-8503 Japan.
Jazyk: angličtina
Zdroj: Nanoscale advances [Nanoscale Adv] 2022 Oct 06; Vol. 4 (24), pp. 5270-5280. Date of Electronic Publication: 2022 Oct 06 (Print Publication: 2022).
DOI: 10.1039/d2na00626j
Abstrakt: L 1 0 -ordered ferromagnetic nanowires with large coercivity are essential for realizing next-generation spintronic devices. Ferromagnetic nanowires have been commonly fabricated by first L 1 0 -ordering of initially disordered ferromagnetic films by annealing and then etching them into nanowire structures using lithography. If the L 1 0 -ordered nanowires can be fabricated using only lithography and subsequent annealing, the etching process can be omitted, which leads to an improvement in the fabrication process for spintronic devices. However, when nanowires are subjected to annealing, they easily transform into droplets, which is well-known as Plateau-Rayleigh instability. Here, we propose a concept of "nanostructure-induced L 1 0 -ordering" of twinned single-crystals in CoPt ferromagnetic nanowires with a 30 nm scale ultrafine linewidth on Si/SiO 2 substrates. The driving forces for nanostructure-induced L 1 0 -ordering during annealing are atomic surface diffusion and extremely large internal stress at ultrasmall 10 nm scale curvature radii of the nanowires. (Co/Pt) 6 multilayer nanowires are fabricated by a lift-off process combining electron-beam lithography and electron-beam evaporation, followed by annealing. Cross-sectional scanning transmission electron microscope images and nano-beam electron diffraction patterns clearly indicate nanostructure-induced L 1 0 -ordering of twinned single-crystals in the CoPt ferromagnetic nanowires, which exhibit a large coercivity of 10 kOe for perpendicular, longitudinal, and transversal directions of the nanowires. Two-dimensional grazing incidence X-ray diffraction shows superlattice peaks with Debye-Scherrer ring shapes, which also supports the nanostructure-induced L 1 0 -ordering. The fabrication method for nanostructure-induced L 1 0 -ordered CoPt ferromagnetic nanowires with twinned single-crystals on Si/SiO 2 substrates would be significant for future silicon-technology-compatible spintronic applications.
Competing Interests: There are no conflicts to declare.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
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