(Invited) Nanostructured Silicon Loaded with FePt Nanoparticles – a Composite with High Energy Product

In this work silicon nanotubes (SiNTs) and porous silicon (PSi) are loaded with Co nanoparticles (NPs) and hard magnetic FePt nanoparticles. These composite systems are used as platform to create 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. These results are compared with the PSi/SiNTs-Co composites. PSi/FePt demonstrates superior hard magnetic behavior with a higher coercivity and remanence compared to SiNTs/FePt. Varying the Fe molar ratio in deposits results in a small variation of the coercivity of about 5%. FePt-loaded samples consistently show increased coercivity and remanence compared to Co-loaded samples, with PSi exhibiting a stronger effect compared to SiNTs. The dependence of the magnetization on the temperature between 4.2 K and 300 K shows a decrease of the coercivity with increasing temperature, which is common for a ferromagnetic behavior. High temperature magnetization measurements allow to determine the Curie Temperature (TC) of PSi and SiNTs loaded with FePt NPs. The PSi templated system offers a lower TC compared to the SiNTs composite system.