Influence of a Driven Magnetic Domain Wall on Resistivity in a Thin Ferromagnetic Wire

Abstract

We study the domain wall (DW) resistivity in a thin wire of disordered ferromagnetic metal, in the presence of an ac magnetic field with the frequency ω_ex applied parallel to the wire. Periodic oscillations of a DW driven by the magnetic field induce spin-flip electron scattering, which increases the resistivity, particularly when ω_ex is nearly equal to the attempt frequency ω₀ of the DW. We calculate the negative correction δ σ to local conductivity due to the spin-flip electron scattering at zero temperature. We find that the correction arising inside the DW region is given by δ σ/σ₀ ∝ -1 /[(1-ω_ex/ω₀)² + (η/ω₀)²], where η is the friction coefficient for the DW motion and σ₀ the Drude conductivity. This result indicates that we can estimate the important parameters ω₀ and η for DW dynamics by measuring the resistivity as a function of ω_ex.