Micromagnetic simulations of hysteresis in an array of cobalt nanotubes

Here we perform modeling of hysteresis measurements, described earlier by Crowley et al., of an array of cobalt nanotubes using a single infinite tube simulation. The modeling has been performed under the assumptions that (i) the long axis of the tube is the hard axis of the anisotropy and (ii) in the experiment we deal with a distribution of different tubes, each having a different anisotropy constant. The best fit to the experimental result is achieved using a log-normal anisotropy distribution, with a peak value close to −0.2 MJ/m3. The distribution parameters are nearly the same for both experimental temperatures, Texp=1.8 and 300 K. These parameters are only weakly dependent on the tube-wall width and the material parameters.