Infiltration of Fe3O4-nanoparticles into porous silicon with respect to magnetic interactions (Nanostructured Thin Films IV)

Official URL: http://dx.doi.org/10.1117/12.895017

Mesoporous silicon (PS) is used as matrix for infiltration of Fe3O4 nanoparticles (5 and 8 nm). The structure and magnetic behaviour of such composites are investigated and a correlation between the morphology of the nanocomposite (structure of the matrices, size and distribution of Fe3O4 particles) and the magnetic properties of the system is figured out. This system shows a superparamagnetic (SPM) behaviour at room temperature and becomes ferromagnetic (FM) at lower temperatures. The transition temperature between SPM and a blocked state depends on the particle size, their coating and on their magnetic interactions. Dipolar coupling between the particles can be influenced by varying the PS morphology as well as by the filling factor. The blocking temperature (TB) of the composite is tuneable and changes due to the variation of dipolar coupling of the Fe3O4-particles (distance between particles). Results gained from electron microscopy and tomography, respectively such as size and spatial distribution of the particles together with the magnetic data lead to a more detailed knowledge of the Fe3O4/silicon nanocomposite system.