Negative Domain Wall Contribution to the Resistivity of Microfabricated Fe Wires

The effect of domain walls on electron transport has been investigated in microfabricated Fe wires (0.65 to 20 mm linewidths) with controlled stripe domains. Magnetoresistance (MR) measurements as a function of domain wall density, temperature, and the angle of the applied field are used to determine the low field MR contributions due to conventional sources in ferromagnetic materials and that due to the erasure of domain walls. A negative domain wall contribution to the resistivity is found. This result is discussed in light of a recent theoretical study of the effect of domain walls on quantum transport. [S0031-9007(98)06392-3]