Origin of ferromagnetism of MnSi_1.7 nanoparticles in Si: First-principles calculations

The origin of the magnetism of MnSi_1.7 nanoparticles in Si is investigated using the first-principles calculations: bulk and interface effects are considered. The bulk magnetic property is expected to be affected by stoichiometry, strain, and charge accumulation. Stoichiometry and charge accumulation induce a ferromagnetic state, and strain stabilizes the ferromagnetic state. Another factor, the MnSi_1.7/Si interface formation, is seen as triggering ferromagnetism strongly localized at the interface. These two mechanisms are shown to be related to the experimentally determined hard and soft components, respectively.