Fe–Co magnetic nanoclusters by density functional theory calculations

Abstract

We present density functional theory results referring to the structural, electronic and magnetic properties of 13, 55, 147 and 309 Fe-Co (magnetic-magnetic) icosahedral nanoclusters (ICO) comparing with our previous results on Fe-Cu (magnetic-nonmagnetic). It came out that the Fe atoms always favour the edge surface sites exhibiting higher average magnetic moment (MM) for Fe and FeCo ICOs than FeCu while the local Fe MM is greater for FeCu12 and Fe6Cu49 ones. This is due to the strong hybridisation of Fe 3d-Co 3d states, while in Fe-Cu the Fe spin down states are restricted close to fermi without been affected by the corresponding Cu states. These results could be used for the design of environmental sustainable smart magnetic alloys.

Ab initio, artificial neural network predictions and experimental synthesis of mischmetal alloying in Sm–Co permanent magnets

“…This fact implies that, theoretically, the RE atoms are not indispensable for the anisotropy, 6 while the use of Co as TM is preferred due to its excellent magnetic properties, arising from its 3d states. [14][15][16][17] As mentioned above, SmCo 5 is currently considered as the most prominent compound of the RE-TM 5 family for PMs due to its excellent hard magnetic properties. Regarding the use of other RE atoms in recent studies, CeCo 5 is an interesting compound, as it presents high values of uniaxial anisotropy and Ce is the most abundant RE element.…”

“…This fact implies that, theoretically, the RE atoms are not indispensable for the anisotropy, 6 while the use of Co as TM is preferred due to its excellent magnetic properties, arising from its 3d states. 14–17…”

Materials characterisation and modelling on the small scale

“…Six manuscripts from symposium D2 describe studies on metallic alloys, semiconductors, as well as oxides: on metals, Wojcik et al [1] describe transmission electron microscopy (TEM) measurements of the sizes and morphologies of γ’ precipitates (Ni 3 (Ti,Al) of ordered L1 2 type), as well as borides at grain boundaries, as function of cooling rates in a new high temperature Ni-base alloy for future turbine blade manufacturing. Cutrano and Lekka [2] employ density functional theory (DFT) to model the electronic and magnetic properties of icosahedral FeCo magnetic nanoclustes and compare them to FeCu clusters and thin films en route to environmentally sustainable smart magnetic alloys. On semiconductors, Norris and Walther [3] present a scanning transmission electron microscopy (STEM) study, applying quantitative X-ray mapping to thin layers of (001) Si 1- x Ge x /Si ( x ≈ 0.3 or x = 1) just above and below the Stranski–Krastanow transition, and compare the results to segregation modelling for different deposition fluxes.…”