Dependence of domain-wall depinning threshold current on pinning profile

Abstract

We have investigated the threshold current density required for depinning a domain wall from constrictions in NiFe nanowires, which give rise to pinning potentials of fixed amplitude but variable profile. We observed it to vary linearly with the angle of the triangular constriction. These results are reproduced using micromagnetic simulations including the adiabatic and nonadiabatic spin-torque terms. By curve-fitting the calculated variations to the experimental results, we obtain the nonadiabaticity parameter β=0.04(±0.005) and current spin polarization P=0.51(±0.02). © 2009 The American Physical Society.