Structural disorder and short-range order in full Heusler alloys Fe2VAl and Co2CrAl from first principles calculations

Abstract

The ordered Fe 2 VAl is a non-magnetic narrow-gap semiconductor. � The ordered Co 2 CrAl is a ferromagnetic semimetal. � Disordered Fe 2 VAl is magnetic metal. � Disordering of Co 2 CrAl decreased its magnetization by 32%. � Short range order raised magnetization in Fe 2 VAl but not in Co 2 CrAl.

On the structure and electronic properties of Fe2V0.8W0.2Al thin films

“…When doped, it displays a thermoelectric power factor -PF = α 2 /ρ ≥ 5 mW m -1 K -2 -larger than in Bi2Te3 4,5 . This feature could be related to a paramagnetic semi-metallic ground state (pseudo-gap ~ 0.2 eV), as obtained by Density Functionnal Theory (DFT) band structure calculations based on the Generalized Gradient Approximation (GGA) [6][7][8][9] . In addition, recent DFT-GGA calculations have shown that its electronic band gap increases with temperature, thus mitigating the otherwise unfavorable bipolar effect 10 .…”

Magnetic Properties of Fe$_2$CrGa Heusler Alloy Films

“…In a disordered state, these «ferromagnetic» atoms can create their own clusters. A strong influence of the atomic order on the magnetic properties of HA has been shown experimentally and explained using the result of the first-principal calculations of the electronic structure and magnetic properties of HAs [2,[4][5][6][7][8][9][10][11][12][13][14].…”

“…It was shown that atomic disorder with a statistical distribution of defects or/and with the formation of some short-range order causes about 30% magnetic moment reduction in Co2CrAl alloy and an appearance of the magnetic moment of about 1.9 µB/f.u. in nonmagnetic Fe2VAl [13]. Ishida et al considered the effect of various kinds of chemical disorder in Fe2CrZ (Z = Si, Ge, Sn) HAs on their electronic structure and some physical properties.…”