Domain propagation in He-ion-bombarded magnetic wires with opposite exchange bias

Abstract

Exchange-biased IrMn/CoFe full films are magnetically structured with He-ion bombardment into stripes with antiparallel-aligned loop shift. The patterning results in a two-step magnetization loop corresponding to two regions of oppositely aligned exchange bias. The longitudinal magnetization reversal through head-on domain-wall motion and partial penetration of magnetization from neighboring strips is highly asymmetric involving ripplelike domain structures and incoherent rotation of magnetization. In addition, Néel-wall-like structures with a preferred sense of rotation are formed at the edges of the strips. Along the transverse direction the reversal is dominated by the switching of the magnetic border structures between the strips. Complicated domain patterns are generated under other external field angles.

Stray fields above artificial magnetic in-plane domains

“…After development of the resist in a 0.9% KOH solution a parallel-stripe structure results, consisting of 5 mm wide resistcovered and 5 mm wide resist-free stripes both having their long axes perpendicular to the initial EB field direction. The thickness of the resist was chosen to prevent 10 keV He þ ions to reach the sample surface in the subsequent bombardment step [14,15,[22][23][24]. The ion bombardment was performed through the resist mask using a home-built plasma source [25].…”

Magnetic patterning by means of ion irradiation and implantation

“…Different kinds of lateral structures are demonstrated in literature, however, the most revealing experiments were performed on stripe-like structures. Therefore, the main focus in this review will be on these quasi 2-dimensional patterns [33,36,38,41,46].…”

Size effects on the magnetization reversal behavior of exchange bias modulated thin films

“…Alternatively, ion bombardment under field exposure has been proven to achieve the same effect, including the substantial advantage of local exchange bias patterning. [21][22][23][24] Yet, ion assisted magnetic patterning inherits secondary effects such as an alteration of saturation magnetization 25,26 or magnetic anisotropy 25,27 of the F layer. A review on further aspects of patterning by ion bombardment can be found in Ref.…”