Study of magnetic, thermoelectric, and mechanical properties of double perovskites Be2XH6 (X = Cr and Mn) for spintronic and hydrogen-storage applications.

[Display omitted] • Be 2 CrH 6 , and Be 2 CrH 6 have hydrogen storage capacities 7.9 wt%, and 7.6 wt%, • Spintronic and energy harvesting applications. • The ferromagnetism by electron spin instead of magnetic ion clustering. • The Half-metallic ferromagnetism ensures 100% spin polarization. • Large power factor and least lattice thermal conductivity. Metal hydrides are highly significant for hydrogen storage because of high gravimetric and kinetic factors. Therefore, the double perovskites hydrides Be 2 XH 6 (X = Cr and Mn) have outstanding hydrogen storage capability with gravimetric hydrogen densities of 7.9 wt% and 7.6 wt%, respectively. Moreover, the DFT-based PBE-GGA and TB-mBJ potential have been implemented to systematically analyze the electronic, Curie temperature, and magnetic characteristics of Be 2 XH 6 (X = Cr and Mn). The tolerance factor and formation energy analysis indicate the structural and thermodynamic stabilities. The band structures, density of states and Curie Weiss law ensure the above room temperature half metallic ferromagnetism with complete spin polarization. The ultralow lattice thermal conductivity and high thermoelectric performance also significantly increase their importance. Finally, the mechanical and thermodynamic behavior have also been addressed in detail. These conclusions are significant for future hydrogen storage growth increases in metal hydrates. [ABSTRACT FROM AUTHOR]