Absence of weak electron localization in ferromagnetic cobalt wires

We have investigated the low-temperature resistance behavior and the magnetoresistance of single-domain cobalt wires of 400 μm length, 2 μm width and thicknesses between 5 nm and 32 nm. A logarithmic resistance increase is observed for temperatures T < 15 K which is consistently explained as originating from enhanced electron-electron interactions (EEI) in two dimensions rather than from weak electron localization (WEL). The results are confirmed for both platinum-capped and un-capped cobalt wires of various thicknesses. Our experimental results are compared with recent theoretical predictions for 2-dimensional ferromagnetic systems.