Effect of Cu-electrodeposition on the magnetic properties of Sr-hexaferrite with porous structure

The magnetic behavior of the strontium hexaferrite (SrM) with foam structure was studied when copper (Cu)coats its surface. Copper was successfully deposited on the walls of the magnetic foam using the electrodepositionmethod. Results suggest that copper begins to nucleate on the hexaferrite grains because of a two steps process;the one based on a driving force of the Cu ions by the effect of the electric field, and secondly, the deposition ofcopper atoms on the non-conductive SrM surface. The SrM and Cu show a hard interaction which modifies themagnetic properties of the SrM foam as copper covers its surface. Hence, the coercive field (Hc ) and the magnetization squareness (Mr/Ms ) have a trend to increase up to a Cu/SrM weight ratio close to 0.5. The dM/dH,M curves (SFD) indicate the presence of two uncoupled magnetic contributions. The copper fixes the magneticmoments of iron at the surface increasing the switching field these particles, whereas in the inner particles themagnetization rotates easily resulting in a widening of the SFD curve