Pt-Fe loaded nanostructured silicon and improvement of the magnetic performance

This work reports the pore-filling of porous silicon (PSi) and the loading of silicon nanotubes (SiNTs) with Pt-Fe nanoparticles (NPs) and the corresponding different magnetic behavior of the two composite systems. The fabrication of magnetic hard/soft nanostructures is in demand for the purpose of achieving both a high energy product as well as the replacement of rare earth permanent magnets. Pt-Fe templated by PSi shows a higher coercivity and remanence than SiNTs/Pt-Fe and thus a higher hard magnetic performance, the difference between coercivities being about 57%. Considering that the Pt-Fe deposits employ different molar ratios of Pt to Fe the coercivities vary in a range of 5% in the case of both template types. Comparing Pt-Fe loaded samples with Co-loaded samples in all cases, an increase of the coercivity and the remanence is observed for Pt-Fe, whereas in the case of PSi as template material the increase is significantly stronger (about twice as much) than in the case of SiNTs samples. Furthermore, the samples are investigated at high temperatures up to 950 K to determine the Curie temperature of the systems. Loading of PSi and SiNTs with PtFe NPs with different molar ratios of the components and investigation of their magnetic behavior, especially with respect to the energy product of the systems is discussed. The differences between the two template systems regarding the magnetic characteristics are figured out. Furthermore a comparison with Co-loaded PSi and SiNTs is presented. High-temperature magnetic measurements are performed especially to determine Curie temperature (TC). image