Lightweight macroporous Co-Pt electrodeposited films with semi-hard-magnetic properties

Macroporous, partially L10-ordered Co-Pt films with nearly equiatomic composition were successfully synthesized by electrodeposition from an aqueous sulfate–chloride electrolyte on colloidal crystal-templated substrates, followed annealing in vacuum. The colloids deposited the substrate consisted of amidine-functionalized polystyrene spheres 215 ± 13 nm diameter, which self-assembled electrophoresis. As-deposited obtained after removal showed a highly-packed arrangement macropores. Structurally, A1-disordered face-centered cubic (fcc) solid solution, accompanied small amounts fcc/hexagonal close-packed (hcp)–Co. Upon at 600 °C, phase partly transformed into (face-centered tetragonal, fct) phase. As result, coercivity significantly increased 148 Oe to 1328 Oe. Importantly, porosity was preserved annealing. Optimum temperature and time selected basis prior parametric study electroplated dense counterparts. This work demonstrates that combination crystal templating is very convenient pathway towards lightweight semi-hard magnets potential technological applications automotive aerospace industries, portable sensors or spectrometers, magnetic levitation systems, magnetoelectric devices, among others.