Engineering the electronic, magnetic and gap-related properties of the quinternary half-metallic Heusler alloys

Abstract

We review the electronic and magnetic properties of the quinternary full Heusler alloys of the type Co${}_2$[Cr${}_{1-x}$Mn${}_x$][Al${}_{1-y}$Si${}_y$] employing three different approaches : (i) the coherent potential approximation (CPA), (ii) the virtual crystal approximation (VCA), and (iii) supercell calculations (SC). All three methods give similar results and the local environment manifested itself only for small details of the density of states. All alloys under study are shown to be half-metals and their total spin moments follow the so-called Slater-Pauling behavior of the ideal half-metallic systems. We especially concentrate on the properties related to the minority-spin band-gap. We present the possibility to engineer the properties of these alloys by changing the relative concentrations of the low-valent transition metal and $sp$ atoms in a continuous way. Our results show that for realistic applications, ideal are the compounds rich in Si and Cr since they combine large energy gaps (around 0.6 eV), robust half-metallicity with respect to defects (the Fermi level is located near the middle of the gap) and high values of the majority-spin density of states around the Fermi level which are needed for large values of the perfectly spin-polarized current in spintronic devices like spin-valves or magnetic tunnel junctions.

17 pages, 10 figures

References in corpus (11)

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• Ab initio prediction of half-metallic properties for the ferromagnetic Heusler alloys Co${}_2$MSi (M=Ti, V, Cr)
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• Doping and disorder in the Co${}_2$MnAl and Co${}_2$MnGa half-metallic Heusler alloys
• Electron Correlations and the Minority-Spin Band Gap in Half-Metallic Heusler Alloys
• Model Hamiltonian parameters for half-metallic ferromagnets NiMnSb and CrO2
• Structural and magneto-transport characterization of Co_2Cr_xFe_(1-x)Al Heusler alloy films

Cited by in corpus (6)

• 3d-electron induced magnetic phase transition in half-metallic semi-Heusler alloys
• Editorial Comment on the Special Issue of "Information in Dynamical Systems and Complex Systems"
• Pressure dependence of Curie temperature and resistivity in complex Heusler alloys
• On the rich magnetic phase diagram of (Ni, Co)-Mn-Sn Heusler alloys
• Defect-induced magnetic structure of CuMnSb
• Volume dependence of magnetic properties in Co2Cr1-xYxGa (Y=Ti-Ni) Heusler alloys: a first-principles study