360º Domain Walls have been reported in the reversal processes of thin
films as a result of pinning defects [1]. Recently they have also been
observed during the reversal process of closed structures even without the
presence of any apparent defects [2]. In terms of their application to
technological devices, the 360º Domain Walls have been proposed to be used
in the fabrication of as magnetic random access memory (MRAM) [3], spin
wave generators [4], magnetic memory recording devices [5] and magnetic
sensors [5].
In this talk I will introduce the main micromagnetic properties of a 360º
Domain Walls and their role in the switching of nanorings driven by
azimuthal fields. A short study on the resilience of this reversal
mechanism under temperature will also be shown. Moreover, the results of a
proposed magnetic memory recording devices based on 360º Domain Walls will
be presented. Finally, initial results on the localized injection of 360º
Domain Walls into stripes will be outlined.
References:
[1] P. Gaunt and C. K. Mylvaganam. Nucleation and pinning at 360◦ domain
walls in SmCo_5 and related alloys. J. Appl. Phys., 48(6):2587–2590, 1977.
[2] F. J. Casta no, C. A. Ross, C. Frandsen, and A. Eilez et al. Metastable
states in magnetic nanorings. Phys. Rev. B, 67(18):184425, May 2003.
[3]T. J. Hayward, J. Llandro, R. B. Balsod, J. A. C. Bland, D. Morecroft,
F. J. Castano, and C. A. Ross. Switchingn behavior of individual
pseudo-spin-valve ring structures. Phys. Rev. B, 74:134405, Oct 2006.
[4] P. E. Roy, T. Trypiniotis, and C. H. W. Barnes. Micromagnetic
simulations of spin-wave normal modes and the resonant field-driven
magnetization dynamics of a 360◦ domain wall in a soft magnetic stripe.
Phys. Rev. B, 82:134411, Oct 2010
[5] C. B. Muratov and V. V. Osipov. Bit storage by 360 domain walls in
ferromagnetic nanorings. IEEE Trans. Magn., 45:3207–3209, 2009
[6] M. Diegel, R. Mattheis, and E. Halder. 360 ◦ domain wall investigation
for sensor applications. IEEE Trans. Magn., vol. 40, no. 4,:2655–2657, 2004.