Spin waves modes in cobalt nanowires arrays

Electrodeposited arrays of ferromagnetic nanowires (NWs) have been largely studied during the two last decades. The NWs effective uniaxial magnetic anisotropy along their axis is a key parameter, which strongly influences their static and dynamic magnetic behaviors. This anisotropy, for a given material, can be controlled by the packing density of the cylinders; this feature is, for instance, expected to be used in microwave absorption devices. These geometrical parameters influence the dipolar interactions between the NWs, proportional to both the magnetization and to the packing density, that become particularly intense when the spacing between the NWs is smaller than the length of one nanowire. Moreover, the respective roles of the crystalline anisotropy and the shape anisotropy are crucial. When they compete (add), the result is a reduction (increase) of the overall anisotropy. In Co-base nanowire arrays, the presence of a defined crystalline anisotropy and texture contributes significantly to determine the magnetization response.