Domain wall creep in magnetic wires -: art. no. 107202

The dynamics of a 1D domain wall (DW) in magnetic wires patterned in 2D ultrathin Co films is studied as a function of the wire width w(0). The DW velocity v(H) is hugely reduced when w(0) is decreased, and its field dependence is consistent with a creep process with a critical exponent mu=1/4. The effective critical field scales as (1/w(0)). Measurements of v(H) in wires with controlled artificial defects show that this arises from the edge roughness introduced by patterning. We show that the creep law can be renormalized by introducing a topologically induced critical field proportional to (1/w(0)).