  We investigate the role of dipolar interactions on the magnetic properties of
nanowires aggregates. Micromagnetic simulations show that dipolar interactions
between wires are not detrimental to the high coercivity properties of magnetic
nanowires composites even in very dense aggregates. This is confirmed by
experimental magnetization measurements and Henkel plots which show that the
dipolar interactions are small. Indeed, we show that misalignment of the
nanowires in aggregates leads to a coercivity reduction of only 30%. Direct
dipolar interactions between nanowires, even as close as 2 nm, have small
effects (maximum coercivity reduction of ~15%) and are very sensitive to the
detailed geometrical arrangement of wires. These results strenghten the
potential of magnetic composite materials based on elongated single domain
particles for the fabrication of permanent magnetic materials.
