Direct observation of stochastic domain-wall depinning in magnetic nanowires.

Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Physical Review Letters (Impact Factor: 7.73). 05/2009; 102(14):147204. DOI: 10.1103/PhysRevLett.102.147204
Source: PubMed

ABSTRACT The stochastic field-driven depinning of a domain wall pinned at a notch in a magnetic nanowire is directly observed using magnetic x-ray microscopy with high lateral resolution down to 15 nm. The depinning-field distribution in Ni80Fe20 nanowires considerably depends on the wire width and the notch depth. The difference in the multiplicity of domain-wall types generated in the vicinity of a notch is responsible for the observed dependence of the stochastic nature of the domain-wall depinning field on the wire width and the notch depth. Thus the random nature of the domain-wall depinning process is controllable by an appropriate design of the nanowire.