Geometric, electronic, and magnetic structure ofCo2FeSi: Curie temperature and magnetic moment measurements and calculations

Abstract

In this work a simple concept was used for a systematic search for new materials with high spin polarization. It is based on two semi-empirical models. Firstly, the Slater-Pauling rule was used for estimation of the magnetic moment. This model is well supported by electronic structure calculations. The second model was found particularly for Co2 based Heusler compounds when comparing their magnetic properties. It turned out that these compounds exhibit seemingly a linear dependence of the Curie temperature as function of the magnetic moment.Stimulated by these models, Co2FeSi was revisited. The compound was investigated in detail concerning its geometrical and magnetic structure by means of X-ray diffraction, X-ray absorption and Mößbauer spectroscopies as well as high and low temperature magnetometry. The measurements revealed that it is, currently, the material with the highest magnetic moment (6µB ) and Curietemperature (1100K) in the classes of Heusler compounds as well as half-metallic ferromagnets. The experimental findings are supported by detailed electronic structure calculations.

The role of chemical structure on the magnetic and electronic properties of Co2FeAl0.5Si0.5/Si(111) interface

“…Co-based Heusler alloys have been attracting a lot of attention due to their predicted 100% spin polarization at the Fermi level, making them an ideal material of choice for many spintronic applications. [1][2][3][4][5] Among the half-metallic ferromagnetic (HMF) full Heusler alloys of the form X 2 YM (X,Y: transition metals, M: main group elements), Co 2 FeAl 0.5 Si 0.5 (CFAS) is of particular interest due to its high Curie temperature T C and giant tunnel magnetoresistance ratio at room temperature when used as an electrode in magnetic tunnel junctions. 6 The integration of HMF materials in existing largescale integrated circuits technologies could enable the development of fast and ultra-low power consumption Si-based spintronic devices.…”

“…It is worth noting that along the [1][2][3][4][5][6][7][8][9][10] orientation of the fully ordered L2 1 phase, where Co, Fe, and Al/Si occupy the X, Y, and M sites, respectively, each atomic column is occupied by single species of Co, Fe, while Al/Si share the same atomic columns. In contrast to L2 1 , for films with B2 ordering, only the Co sub-lattice (populating the X sites) is fully ordered, whilst the Fe and Al/Si atomic species are intermixed (Y-M atomic sites mixing).…”

Giant coercivity enhancement and dimensional crossover of superconductivity in Co2FeSi-NbN nanoscale bilayers

“…Recently, our group has explored the use of the Co-based Heusler compound (Co 2 MnSi) electrodes for efficient injection of pure spin currents into superconducting NbN 11 . NbN is a type II superconductor of short coherence length ( (0) 5 nm) and long penetration depth ( (0) 200 nm) while Co 2 FeSi (CFS) is a ferromagnet of the Heusler family with high magnetic ordering temperature 1150 K and saturation magnetization 6 µ B per formula unit 12 . In the present work we investigate the nature of proximity coupling and its influence on magnetic switching dynamics in the hitherto unexplored NbN/Co 2 FeSi bilayers grown on (100) MgO.…”

Investigation of Co2FeSi: The Heusler compound with highest Curie temperature and magnetic moment

“…Regarding the re- The experimental magnetic moment is supported by band structure calculations revealing a HMF character with a magnetic moment of 6µ B . The results of these calculations will be given elsewhere [15].…”