Ground state properties and thermoelectric behavior of Ru2VZ (Z=Si, ge, sn) half-metallic ferromagnetic full-Heusler compounds

• The ground state and thermoelectric properties are reported for the first time.
• Ru2VZ are found to be a half-metallic ferromagnetic full Heusler compound.
• The total spin magnetic moment satisfies the Slater–Pauling rule for Ru2VZ.
• The TC is found to be 23 K, 126 K and 447 K for Ru2VSi, Ru2VGe and Ru2VSn.
• ZTMAX values of 0.016, 0.033 and 0.063 are achieved for Ru2VSi, Ru2VGe and Ru2VSn.

The ground state properties namely structural, mechanical, electronic and magnetic properties and thermoelectric behavior of Ru2VZ (Z=Si, Ge and Sn) half-metallic ferromagnetic full-Heusler compounds are systematically investigated. These compounds are ferromagnetic and crystallize in the Heusler type L21 structure (prototype: Cu2MnAl, Fm-3m 225). This result is confirmed for Ru2VSi and Ru2VSn by experimental work reported by Yin and Nash using high temperature direct reaction calorimetry. The studied materials are half-metallic ferromagnets with a narrow direct band gap in the minority spin channel that amounts to 31 meV, 66 meV and 14 meV for Ru2VSi, Ru2VGe, and Ru2VSn, respectively. The total spin magnetic moment (Mtot) of the considered compounds satisfies a Slater–Pauling type rule for localized magnetic moment systems (Mtot=(NV−24)µB), where NV=25 is the number of valence electrons in the primitive cell. The Curie temperature within the random phase approximation (RPA) is found to be 23 K, 126 K and 447 K for Ru2VSi, Ru2VGe and Ru2VSn, respectively. Semi-classical Boltzmann transport theories have been used to obtain thermoelectric constants, such as Seebeck coefficient (S), electrical (σ/τ) and thermal conductivity (κ/τ), power factor (PF) and the Pauli magnetic susceptibility (χ). ZTMAX values of 0.016 (350 K), 0.033 (380 K) and 0.063 (315 K) are achieved for Ru2VSi, Ru2VGe and Ru2VSn, respectively. It is expected that the obtained results might be a trigger in future experimentally interest in this type of full-Heusler compounds.

Temperature dependence of figure of merit for Ru2VZ (Z=Si, Ge, and Sn) compounds.Figure optionsDownload as PowerPoint slide