Al${}_2$MnCu: A magnetically ordered member of the Heusler alloy family despite having a valence electron count of 24

Abstract

The magnetic property of the Heusler alloys can be predicted by the famous Slater-Pauling (S-P) rule, which states the total magnetic moment ($m_t$) of such materials can be expressed as $m_t=(N_V-24){\mu }_B/f.u.$, where $N_V$ is the total valence electron count (VEC). Consequently, no Heusler alloys having VEC = 24 are theoretically expected as well as experimentally reported to have any magnetic ordering. Recently, a special class of Heusler alloys with 50\% concentration of $p$-block elements (anti-Heusler) have been identified, although none of such reported compounds belong to the VEC 24 category. Here, we report a new anti-Heusler alloy, Al${}_2$MnCu, that undergoes long-range ferromagnetic (FM) ordering with $T_{\mathrm{C}}\sim$315 K and a large magnetic moment of $\sim$1.8 ${\mu }_B$/f.u. despite having VEC 24. A phenomenological model based on molecular orbital hybridization is also proposed to understand the magnetism and unusual deviation from the standard S-P rule.

11 pages, 14 figures

References in corpus (9)

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Cited by in corpus (2)

• Co${}_2$MnZ (Z = Al, Si, Ga, Ge, Sn) Heusler alloys as candidate materials for spintronic and microelectronic applications: Electronic structure, transport, and magnetism
• Disproportionate influence of site disorder on the evolution of magnetic phases in anti-Heusler alloy Al${}_2$MnFe