Resistivity due to domain wall excitation in thin wires of ferromagnetic metals

We study the influence of thermal excitation of a domain wall (DW) on resistivity in thin wires of disordered ferromagnetic metals. The negative correction for local conductivity ba due to the DW excitation is calculated by assuming that the elastic mean free time of spin-up electrons tau+ differs from that of spin-down electrons tau (-). When k(B)T much greater than h omega (0) (omega (0): attempt frequency of the DW) we obtain the correction arising inside the DW region as delta sigma/sigma (o) = -cT/E-pin ,where c approximate to (tau (+) - tau (-))(2)/(6 tau (+)tau (-)), sigma (0) and E-pin denote Drude conductivity and the pinning energy for the DW, respectively. A magnetic field H parallel to the wire reduces E-pin and thereby enhances the negative correction. When H is close to the coercive field H-c, we find that delta sigma>(*) over bar * (H)/sigma (o) proportional to -(1- H/H-c)(-1/2) as long as the DW is trapped at the pinning site.