  We establish a method to produce cylindrical magnetic nanowires displaying
several segments, with a large versatility in terms of segment diameter and
length. It is based on electroplating in alumina templates, the latter being
prepared by several steps of anodization, wet etching and atomic layer
deposition to produce, widen or shrink pores, respectively. We propose an
analytical model to analyze the in-plane and out-of-plane magnetization loops
of dense assemblies of multisegmented wires. The model considers inter-wires
dipolar fields, end-domain curling and predicts the switching field of
individual wires with no adjustable parameter. Its ingredients are crucial to
extract reliable parameters from the fitting of loops, such as magnetization or
the porosity of the array.
