Spin Waves Modes in Cobalt Nanowires Arrays

Cobalt nanowires (NWs) of 40–50 nm average diameter and several micrometers in length were elaborated by electrodeposition process in alumina templates. X-ray diffraction measurements show that all the NWs present a heterogeneous crystalline structure with hcp phase that can be tuned by an appropriate choice of the electrolyte pH. A complex evolution of the magnetic coercivity and squareness with pH is observed in connection with that of the hcp
c
-axis of the crystalline structure. The spin waves (SWs) propagating into the NWs were investigated by means of the Brillouin light scattering technique. A detailed analysis of the SW spectra allows the identification of dipolar and exchange nature modes propagating within the NWs. Their frequency behavior is successfully described by means of analytical models.