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Spintronics is a rapidly developing field in advanced technology. It focuses on manipulating the spin of electrons to achieve high-speed data transfer, handling, and storage in order to enhance its capabilities. We conducted a systematic investigation of the ferromagnetism, electronic, and thermoelectric characteristics of spinel compounds LiFe 2 (O/S) 4. Our analysis for optimization demonstrates that ferromagnetic states exhibit great energy release compared to the antiferromagnetic states, indicating the presence of ferromagnetic behavior in the studied compounds. To evaluate the presence of ferromagnetism above room temperature, we employ the Heisenberg model to calculate the Curie temperature and spin polarization to evaluate the presence of ferromagnetism above room temperature. Additionally, a concise overview of the nature of ferromagnetism, including band structures, density of states, exchange energies and constants, hybridization double exchange model, and crystal-field energy, is provided in this research. The absorption of a shift in magnetic moment from Fe to the Li and O/S sites suggests that the ferromagnetic behavior is primarily due to the spin of electrons. Furthermore, we explore the impact of the thermal parameters on the electro-spin as well as the thermoelectric characteristics for both spin-down and spin-up states, providing insights into the energy-harvesting potential. • Half-metallic ferromagentic spinels LiFe 2 (O/S) 4. • Elastic constant are investigated for structural stability. • Electronic and magnetic properties for spintronic applications. • Magnetic moments are discussed for both compounds. • The electronic and lattice thermal conductivity are calculated for thermoelectric characteristics. [ABSTRACT FROM AUTHOR]

Spintronic is the developing technology which probes the properties of quantum devices with spin of electrons which reduce the size and enhance its speed. Therefore, here the role of 5d electrons and thermoelectric characteristics of double perovskites (DPs) K 2 ZCl/Br 6 (Z = Ta, W, Re) elaborated comprehensively by density functional theory (DFT). The Heisenberg model spin polarization density (SP) has been applied to evaluate the Curie temperature (T c) and spin polarization factor. The tolerance factor (t F) and formation energy (ΔH) have been calculated to confirm the stability of structures. Ferromagnetism has been discussed in terms of spin polarization, crystal field energy (Δ CF) and exchange energies (Δ(d), Δ(pd)). The double exchange mechanism, and exchange constants ensure the role of electrons spin in ferromagnetism instead of segregation of transition metal ions. The transferring of magnetic moments of transitions metals to nonmagnetic sites (K, Cl, Br) show the exchange of spin of electrons and integer values of total magnetic moment show 100 % spin polarization. Finally, the transport properties are studied in standings of electrical and thermal conductivities. The large value of Seebeck coefficient and power factor ensure the importance of studied DPs for thermoelectric generators. • Spintronic and energy harvesting applications. • Large value of Curie temperature and high spin polarization. • The ferromagnetism by electron spin instead of magnetic ion clustering. • Half metallic ferromagnetism evidence complete spin polarization. • Ultralow low values of thermal conductivity and Large power factor. [ABSTRACT FROM AUTHOR]

The double perovskites (DPs) have become emerging aspirant for spintronic technology because of their stable, and multifunctional properties. Here in present article, the role 5d-electrons of Ta, W, Re, and Os in ferromagnetism, and thermoelectric behavior has been illustrated briefly. The ideal values of tolerance factor, formation energy and phonons dispersions are reported for structural, thermodynamic, and lattice dynamic stabilities. The higher Curie temperature and spin polarization has been addressed by Heisenberg model and spin density calculations. The ferromagnetism has been explained by the metallic and insulating channels of spin up and spin down configuration through hybridization, exchange energies, and exchange constants. The shifting of magnetic moments from Cr and X sites to Ba, O and interstitial sites ensures the exchange coupling due to spin of electrons rather than clustering. Furthermore, thermoelectric effect on the spin degree of electrons and transport characteristics are calculated by BoltzTraP code. • Above room temperature ferromagnetism. • Spin of electrons dominant the charge. • Electron spin instead of magnetic ion clustering. • Half metallic ferromagnetism evidence 100% spin polarization. • Ultralow low values of thermal conductivity. [ABSTRACT FROM AUTHOR]

In this study, density functional theory (DFT) showed that the electronic band profiles of CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co, and Ni) indicate their half-metallic character. The optimized magnetic energy curves in different magnetic phases demonstrated the type-I ferrimagnetic order of all the compounds investigated in this study. The magnetic exchange coupling constants were calculated between the Cu–B, B–Re, and Cu–Re site spins using the Heisenberg model. These interactions generate strong long range Cu(↑)B(↑)Re(↓) order through a super-exchange mechanism. In these perovskites, the anti-parallel moments of Re with B and Cu reduce the net magnetic moments and they are responsible for the ferrimagnetism. The Cu and B 3d-electrons are localized and responsible for the magnetism, and the Re 5d-electrons are delocalized and responsible for the metallic nature. Magnetic susceptibility analysis verified the results estimated using DFT and the Heisenberg model. Due to the 100% spin polarization around the Fermi level, high Curie temperature TC and ferrimagnetism are expected, thereby making these materials suitable for spintronic applications. • The half-metallic character of the CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co and Ni) was revealed by DFT. • Heisenberg model was used for the calculating of the magnetic exchange coupling constants. • It has been shown the perspectives of the CaCu 3 B 2 Re 2 O 12 (B = Mn, Fe, Co and Ni) in spintronic applications. [ABSTRACT FROM AUTHOR]