Synthesis, Characterization, Magnetic, Elastic, and Electronic Properties of La₂ZnMnO₆ Double Perovskite

The perovskite La₂ZnMnO₆ was successfully synthesised using the conventional solid-state reaction. X-ray diffraction shows that the perovskite La₂ZnMnO₆ crystallizes in a monoclinic structure P2₁/n space group, where Zn and Mn atoms are regularly distributed. The Raman spectrum result reveals three peaks at 696 cm⁻¹, 655 cm⁻¹ and 505 cm⁻¹, corresponding to the A_g stretching mode, B_g anti-stretching, and bending vibrations modes of Ni/Co-O and Mn-O bonds in the structure. The experimental value of the band gap energy was calculated using Tauc’s formula and the result reveals a semiconducting behaviour. We investigated the structural, elastic, magnetic, and electronic properties using the spin-polarized density functional theory. The partial density of state indicates that the material exhibits a antiferromagnetic semiconducting behaviour. The antiferromagnetic ordering is explained by the super-exchange interaction between empty e_g orbitals of Mn⁴⁺( \({t}_{2 g}^{3}\) $t_{2g}^3$ \({e}_{g}^{0}\) $e_g^0$ ). The obtained Neel temperature is T_N ∼ 28 K which is comparable with the experiment results. Elastic constants and their derivative parameters show a high mechanical stability of this material with a ductile nature. The investigation of the transport properties encompassed an analysis of the electrical conductivity, the figure of merit, the Seebeck coefficient, and thermal conductivity. The results show that electronic and thermal conductivities increase linearly with temperature. The computed values of the figure of merit are close to unity, suggesting that this material is a promising candidate for thermoelectric application.