Dependence of hard-axis anisotropy field on domain wall width for current-induced domain wall motion in nanowires

The dependence of the hard-axis anisotropy field on the domain wall width for current-induced domain wall motion in perpendicularly magnetized anisotropic nanowires was investigated using micromagnetic simulations. The hard-axis anisotropy field in nanowires was estimated by varying the magnetic anisotropy constant and the exchange stiffness constant, and the hard-axis anisotropy constant was calculated from the energy differences of the Bloch and Neel walls. As a result, when the stable domain wall is a Bloch wall, the hard-axis anisotropy field and the intrinsic critical current velocity decrease with increasing domain wall width, whereas when the stable domain wall is a Neel wall, they increase with increasing domain wall width. It was clarified that the intrinsic critical current velocity can be expressed as a function of the domain wall width, even though the analytical solution indicated that the critical current velocity would be monotonically reduced by decreasing the domain wall width. (C) 2013 Elsevier B.V. All rights reserved.