Strain Anisotropy and Magnetic Domains in Embedded Nanomagnets. Issue 52 (11th November 2019)

• Record Type: Journal Article
• Authors: Nord, Magnus; Semisalova, Anna; Kákay, Attila; Hlawacek, Gregor; MacLaren, Ian; Liersch, Vico; Volkov, Oleksii M.; Makarov, Denys; Paterson, Gary W.; Potzger, Kay; Lindner, Jürgen; Fassbender, Jürgen; McGrouther, Damien; Bali, Rantej
• Is Part Of: Small. Volume 15:Issue 52(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-11
• Subjects: curved magnets -- embedded nanomagnets -- ion‐induced patterning -- magnetic domains -- strain anisotropy; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201904738
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Nanoscale modifications of strain and magnetic anisotropy can open pathways to engineering magnetic domains for device applications. A periodic magnetic domain structure can be stabilized in sub‐200 nm wide linear as well as curved magnets, embedded within a flat non‐ferromagnetic thin film. The nanomagnets are produced within a non‐ferromagnetic B2‐ordered Fe60 Al40 thin film, where local irradiation by a focused ion beam causes the formation of disordered and strongly ferromagnetic regions of A2 Fe60 Al40 . An anisotropic lattice relaxation is observed, such that the in‐plane lattice parameter is larger when measured parallel to the magnet short‐axis as compared to its length. This in‐plane structural anisotropy manifests a magnetic anisotropy contribution, generating an easy‐axis parallel to the short axis. The competing effect of the strain and shape anisotropies stabilizes a periodic domain pattern in linear as well as spiral nanomagnets, providing a versatile and geometrically controllable path to engineering the strain and thereby the magnetic anisotropy at the nanoscale. Abstract : Nanomagnets of desired geometries can be embedded within non‐ferromagnetic B2 Fe60 Al40 templates by locally inducing disorder using a focused Ne + ‐ion beam. Penetrating ions cause site‐swapping between Fe and Al atoms as well as a lattice expansion. The lattice expansion is larger along the narrower dimension of the nanomagnet, giving rise to a magnetic anisotropy that manifests periodic magnetic domains.