Dipolar interactions in magnetic nanowire aggregates

We investigate the effect of dipolar interactions on the magnetic properties of nanowire aggregates. Micromagnetic simulations show that dipolar interactions between wires are not detrimental to the high coercivity properties of magnetic nanowires, 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 similar to 15%) and are very sensitive to the detailed geometrical arrangement of the wires. These results strengthen the potential of elongated single domain particles for applications requiring high coercivity properties. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3671540]