Effect of shape anisotropy on threshold current density for current-induced domain wall motion

Using micromagnetic simulations, the authors investigate the effects of the shape anisotropy of nanowires on the threshold current density (J(C)) in the adiabatic limit. It is observed that the type of domain wall significantly affects the dependence of J(C) on the shape anisotropy. For a transverse wall, J(C) is proportional to the shape anisotropy, but slightly deviates from the theoretical prediction [G. Tatara and H. Kohno, Phys. Rev. Lett. 92, 086601 (2004)] possibly due to antivortex formation. For a vortex wall, J(C) is almost independent of the shape anisotropy, as experimentally observed [A. Yamaguchi et al., Jpn. J. Appl. Phys. Part 1 45, 3850 (2006)]. Interestingly, J(C) and the velocity of the vortex wall at finite temperatures are in good agreement with the experimental values even when the nonadiabatic spin torque is not considered. (c) 2007 American Institute of Physics.