  In the present work, we report on the in situ magnetic force microscopy (MFM)
study of the magnetization reversal in two-dimensional arrays of ferromagnetic
Ni80Fe20 and Co55Fe45 nanowires(NW) with different diameters (40, 50, 70 and
100 nm) deposited inside low porosity (P<1%) nanoporous polycarbonate
membranes. In such arrays, the nanowires are sufficiently isolated from each
other so that long range dipolar interactions can be neglected. The MFM
experiments performed for different magnetization states at the same spot of
the samples are analysed to determine the switching field distribution (SFD).
The magnetization curves obtained from the MFM images are relatively square
shaped. The SFD widths are narrower compared to those obtained for high density
arrays. The weak broadening of the curves may be ascribed to the NW intrinsic
SFD. The influence of diameter and composition of the ferromagnetic NW is also
investigated.
