Hard Magnetic FePt Nanoparticles within Nanostructured Silicon to Improve the Maximum Energy Product

In this work nanostructured silicon, silicon nanotubes (SiNTs) and porous silicon (PSi), with embedded hard magnetic FePt nanoparticles (NPs) is used as platform to create hard magnetic nanomagnet-arrays. The magnetic response of FePt-loaded composite materials is investigated, which have potential in high-performance magnets and as rare earth magnet alternatives. PSi/FePt demonstrates superior hard magnetic behavior with a higher coercivity and remanence compared to SiNTs/FePt. Varying the Fe:Pt molar ratio in deposits results in a small coercivity (HC) change. FePt-loaded samples consistently show increased coercivity and remanence compared to Co-loaded samples, with PSi exhibiting a stronger effect compared to SiNTs. Comparing FePt-loaded samples with Co-NP-loaded samples, in both template types an increase of the coercivity is observed for FePt. Also in the case of Co-loading the utilization of PSi offers higher coercivities compared to SiNTs. From the investigated composite systems the ones consisting of PSi and FePt offer the highest energy product.