Spin-Exchange Interaction between Transition Metals and Metalloids in Soft-Ferromagnetic Metallic Glasses
High-performance magnetic materials have immense industrial and scientific importance in wide-ranging electronic, electromechanical, and medical device technologies. Metallic glasses with a fully amorphous structure are particularly suited for advanced soft-magnetic applications. However, fundamental scientific understanding is lacking for the spin-exchange interaction between metal and metalloid atoms, which typically constitute a metallic glass. Using an integrated experimental and molecular dynamics approach, we demonstrate the mechanism of electron interaction between transition metals and metalloids. Spin-exchange interactions were investigated for a Fe-Co metallic glass system of composition [(Co1-xFex)0.75B0.2Si0.05]96Cr4. The saturation magnetization increased with higher Fe concentration, but the trend significantly deviated from simple rule of mixtures. Ab initio molecular dynamics simulation was used to identify the ferromagnetic/anti-ferromagnetic interaction between the transition metals and metalloids. The overlapping band-structure and density of states represent 'Stoner type' magnetization for the amorphous alloys in contrast to 'Heisenberg type' in crystalline iron. The enhancement of magnetization by increasing iron was attributed to the interaction between Fe 3d and B 2p bands, which was further validated by valence-band study.
S. Das et al., "Spin-Exchange Interaction between Transition Metals and Metalloids in Soft-Ferromagnetic Metallic Glasses," Journal of Physics: Condensed Matter, vol. 28, no. 21, Institute of Physics Publishing, May 2016.
The definitive version is available at http://dx.doi.org/10.1088/0953-8984/28/21/216003
Center for High Performance Computing Research
Keywords and Phrases
Ab Initio Molecular Dynamics; Charge Density; Magnetic Properties; Metallic Glass; Spin-Exchange Interactions
International Standard Serial Number (ISSN)
Article - Journal
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