Ferromagnetically correlated clusters in semi-metallic Ru2NbAl Heusler alloy

Abstract

In this work, we report the structural, magnetic and electrical and thermal transport properties of the Heusler-type alloy Ru2NbAl. From the detailed analysis of magnetization data, we infer the presence of superparamagnetically interacting clusters with a Pauli paramagnetic background, while short-range ferromagnetic interaction is developed among the clusters below 5 K. The presence of this ferromagnetic interaction is confirmed through heat capacity measurements. The relatively small value of electronic contribution to specific heat, gamma (~2.7 mJ/mol-K2), as well as the linear nature of temperature dependence of Seebeck coefficient indicate a semi-metallic ground state with a pseudo-gap that is also supported by our electronic structure calculations. The activated nature of resistivity is reflected in the observed negative temperature coefficient and has its origin in the charge carrier localization due to antisite defects, inferred from magnetic measurements as well as structural analysis. Although the absolute value of thermoelectric figure of merit is rather low (ZT = 5.2*10-3) in Ru2NbAl, it is the largest among all the reported non-doped full Heusler alloys.

25 pages, 14 figures

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Cited by in corpus (9)

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• Rare observation of spin-gapless semiconducting characteristics and related band topology of quaternary Heusler alloy CoFeMnSn
• Superparamagnetic and metal-like Ru2TiGe: a propitious thermoelectric material
• 4d-element induced improvement of structural disorder and development of weakly re-entrant spin-glass behaviour in NiRuMnSn
• Al${}_2$MnCu: A magnetically ordered member of the Heusler alloy family despite having a valence electron count of 24
• Restructuring disorder: Transformation from the antiferromagnetic order in Fe2VSi to the ferromagnetic state in FeRuVSi by substitution of a non-magnetic element
• Half-metallicity and wandering axis ferromagnetism in Fe${}_2$Ti${}_{1-x}$Mn${}_x$Sn (0 $<x\le$ 0.3) Heusler Alloys
• Disproportionate influence of site disorder on the evolution of magnetic phases in anti-Heusler alloy Al${}_2$MnFe
• Observation of Griffiths-like phase in the quaternary Heusler compound NiFeTiSn