Tuning the magnetic properties of half-metallic semi-Heusler alloys by sp-electron substitution: The case of AuMnSn${}_{1-x}$Sb${}_x$ quaternary alloys

Abstract

We study the electronic and magnetic properties of the quaternary AuMnSn${}_{1-x}$Sb${}_x$ Heusler alloys using first principles calculations. We determine their magnetic phase diagram and we show that they present a phase transition from a ferromagnetic to an antiferromagnetic state with increasing Sb concentration. For large Sb concentrations the antiferromagnetic superexchange coupling dominates over the ferromagnetic RKKY-like exchange mechanism. This behavior is similar to the one demonstrated by the isovalent Ni${}_{1-x}$Cu${}_x$MnSb alloy studied recently by the authors [I. Galanakis et al, Phys. Rev. B. \textbf{77}, 214417 (2008)]. Thus the variation of the concentration of the \textit{sp}-electrons (Sn and Sb atoms) and the variation of the concentration of the non-magnetic \textit{3d} atoms (Cu) lead to a similar tuning of the the magnetic properties of the Heusler alloys. We show that the inclusion of correlation effects does not alter the phase diagram. Calculated results are in good agreement with the available experimental data.

References in corpus (6)

• Origin and Properties of the Gap in the Half-Ferromagnetic Heusler Alloys
• Role of the conduction electrons in mediating exchange interactions in Heusler alloys
• 3d-electron induced magnetic phase transition in half-metallic semi-Heusler alloys
• Semimetalic antiferromagnetism in the half-Heusler compound CuMnSb
• Magnetic phase diagram of the semi-Heusler alloys from first-principles
• Semiclassical interferences and catastrophes in the ionization of Rydberg atoms by half-cycle pulses