Exploring the thermoelectric performance of NiFeMnAl and ZnFeVAl as novel quaternary Heusler compounds

Quaternary Heusler (QH) compounds, characterized by the chemical formula XX’YZ, are highly regarded in the energy materials sector due to their versatile electronic structures. The current study focuses on synthesizing novel QH compounds, NiFeMnAl and ZnFeVAl, through arc-melting followed by hot-pressing at 1073 K. Maximum Seebeck coefficients were exhibited ∼ −20.48 μV/K and ∼ −17.25 μV/K at 773 K for ZnFeVAl and NiFeMnAl, respectively. The evaluated power factor was ∼ 0.058 mWm⁻¹K⁻² for NiFeMnAl and ∼ 0.020 mWm⁻¹K⁻² for ZnFeVAl at 773 K. Furthermore, the lattice thermal conductivity (κ_l) was exhibited ∼ 8.73 Wm⁻¹K⁻¹ for NiFeMnAl and ∼ 6.92 Wm⁻¹K⁻¹ for ZnFeVAl at 773 K, with ZnFeVAl exhibiting a ∼ 20.73 % lower κ_l attributed to chemical bonding distortion arising from differences in constituent element electronegativity. Hence, these novel compounds offer a promising avenue for further research in TE materials, aiming to realize higher-performance materials for practical TE device applications.