  We deduce the intrinsic conductivity properties of the ferroelectric domain
walls around the topologically protected domain vortex cores in multiferroic
YMnO3. This is achieved by performing a careful equivalent-circuit analysis of
dielectric spectra measured in single-crystalline samples with different vortex
densities. The conductivity contrast between the bulk domains and the less
conducting domain boundaries is revealed to reach up to a factor 500 at room
temperature, depending on sample preparation. Tunneling of localized defect
charge carriers is the dominant charge-transport process in the domain walls
that are depleted of mo-bile charge carriers. This work demonstrates that via
equivalent-circuit analysis, dielectric spectroscopy can provide valuable
information on the intrinsic charge-transport properties of ferroelectric
domain walls, which is of high relevance for the design of new
domain-wall-based microelectronic devices.
