Magnetisation reversal processes in saturation magnetisation reduced stripes


Magnetisation reversal processes in saturation magnetisation reduced stripes

Basith, M.; Mcvitie, S.; Strache, T.; Fritzsche, M.; McCord, J.; Fassbender, J.

On a continuous 20 nm thick Permalloy film, magnetically softer and harder stripes, which are in direct lateral contact by means of exchange coupling, were fabricated by focused Ga+ irradiation. The irradiation dose was 6.00 x 1015 Ga/ions and the width of the alternative exposed and unexposed stripes were varied from 1000nm to 200nm. Low angle electron diffraction experiment confirmed that due to this amount of ion dose, saturation magnetic induction of the irradiated stripe is reduced to 70 % of the unirradiated stripe, assuming a thickness reduction of 2.5 nm determined by AFM. Magnetisation reversal experiments were carried out using high resolution Lorentz microscopy. For a stripe width of 1000 nm a pronounced 2 step reversal with an intermediate antiparallel orientation of magnetisation in neighboring stripes is found. Differential phase contrast (DPC) images demonstrate a transition from the discrete switching of the wider nanostripes to the collective switching of the narrower stripes of width 200 nm. This can be attributed to the local modification of the magnetic thin film parameters below the intrinsic magnetic length scales associated with the domain wall width. By using DPC mode of Lorentz microscopy, domain wall width was calculated and compared with theory for 20 nm thick continuous Permalloy film.

  • Lecture (Conference)
    Condensed Matter and Materials Physics (CMMP 2010), 14-16 December 2010, 15.12.2010, Warwick, UK

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Publ.-Id: 15139