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The spintronic is an emerging technology which controls the properties of multifactional devices with spin of electrons. In present manuscript, Wien2k and Boltz Trap codes are used to explore electronic, magnetic, and thermoelectric characteristics of Sr 2 CrXO 6 (X = Nb, Mo) double perovskites (DPs). The evaluation of energies released in paramagnetic (PM), antiferromagnetic (AFM), and ferromagnetic (FM) states assure the stability of FM states. Both the negative formation energy and the tolerance factor confirm structural and thermodynamic stability in FM states. The 100 % spin polarization was confirmed by both integer values of magnetic moment (MM) and the spin polarization factor. The values of exchange energy, double exchange model, hybridization of p-d states, and exchange constants are calculated to explore the nature of ferromagnetism and spin functionality. The effect of thermoelectric parameters on spin of electrons and thermoelectric performance are elaborated by thermal to electrical conductivity ratio, Seebeck coefficient and power factor. • High Curie temperature, and spintronic applications. • Spin of electrons overcome the charge with multifuctional properties. • Double exchange mechanism confirms the ferromagnetism by electron spin instead of magnetic ion clustering. • Half metallic ferromagnetism and 100 % spin polarization. • Large value of electrical conductivity and low values of thermal conductivity. [ABSTRACT FROM AUTHOR]

Harvesting waste heat back into electricity by exploiting the temperature difference across two ends of a nanodevice and its concomitant spin dependence has led to the emergence of a new field known as spin caloritronics. Herein, we report the spin polarized thermoelectric features in a π-stacked system comprised of (C n -C 6 H 6 –Fe–C 6 H 6 –C 13-n) n = 2. A decisive factor, the Seebeck coefficient, becomes fully spin dependent on temperature and switches from positive to negative values, which illustrates the switching of the thermoelectric behavior from a p-to n-type due to the change in the spin state from spin-down to spin-up. A relatively large thermoelectric figure of merit has been reported in the case of the spin figure of merit of the system. In this context, three major observations have been made: i) The Seebeck coefficient has a distinctive feature over two different spin channels, ii) the spin Seebeck coefficient (S s) is nearly four times larger than the charge Seebeck coefficient (S c), and (iii) the spin thermoelectric figure of merit (Z S) rises by 80% with respect to charge thermoelectric figure of merit (Z C) under thermal bias. Our results have been well explained through the analysis of temperature dependent transmission spectra of the system. The emergence of a relatively large spin Seebeck coefficient allows us to measure the pure spin current of the system as well as extending the devices application from simple memory (MRAM) devices to on-chip energy harvesting systems. Variation in the spin and charge thermoelectric figure of merit and spin dependent Seebeck coefficient with thermal bias. [Display omitted] • A clean and green energy solution to the massive waste heat generated in a circuit is thermoelectric materials. • Modification in thermoelectric feature against the spin polarization of tunneling electron has developed a new but virgin domain of Spincaloritronics. • Thermoelectric features are analysed mainly through ZT, spin polarized electrical conductivity, spin polarized Seebeck coefficient, In Spincaloritronics, one would have separate figure of merit for charged part and spin part as well as separate charge and spin Seebeck coefficient. • On an average Spin Seebeck coefficient (S s) is approximately four times larger than its charge counterpart (S c) and there is nearly 80% rise in Z S from Z C. Most, significant observation is switching in thermospin behavior from n to p type due to spin reversal. • Dissimilar behavior over two different spin channels certainly exemplify the appearance of spin dependent Seebeck effect with switching action from p to n type due to spin reversal. [ABSTRACT FROM AUTHOR]

In the present work, theoretical investigations of structural, electronic, magnetic, and thermoelectric properties of Cd 0.875 TM 0.125 O (TM = Mn, Fe, Co, Ni) half-metallic ferromagnets are done using WIEN2K code. The computed results when compared with the reported theoretical works reveal consistency. The band structures for spin up (↑), and spin down (↓) channels reveal the half metallic (Mn, Co, Fe), and frustrated (Ni) magnetism. The nature of magnetism has been analyzed in terms of hybridization among 3d states of TMs, individual Cd (5s, 4d) states, and O (2p) states. The control and function of the electron spin are revealed by calculating exchange energies (Δ x (d), Δ x (pd)), crystal field energy (ΔE cryst) and exchange constant (N o α, N o β), those play a very crucial role in understanding the magnetic nature. Moreover, double exchange and RKKY models are discussed to justify the observed half-metallic, and metallic behaviors, which are responsible for the magnetic moments to stabilize a magnetic polarization. The influence of electron spin is explained using the computed electrical and thermal conductivities, while thermoelectric power is elaborated by computing Seebeck coefficient and power factor. • Above room temperature ferromagnetism, and spintronic applications •Quantum spin of electrons dominant the charge with multifuctional properties •Exchange mechanism certifies the ferromagnetism by electron spin instead of magnetic ion clustering •Half metallic ferromagnetism and 100% spin polarization •Large value of electrical conductivity and ultralow low values of thermal conductivity. [ABSTRACT FROM AUTHOR]

The structural, electronic, magnetic, elastic and thermoelectric properties of full-Heusler alloys Co 2 ZrZ (Z = Al, Si, Ga and Sn) are investigated using the augmented plane wave method (FP-LAPW) based on the framework of spin density functional theory. The term of the exchange and correlation potential (XC), is treated by the generalized gradient approximation GGA and Trans-Blaha-modified Becke–Johnson (TB-mBJ). The results obtained showed that the Cu 2 MnAl-type structure has more stable energy than the Hg 2 CuTi-type structure for all the full-Heusler studied. From electronic calculations, it is found that all the compounds studied have an indirect band gap with a half-metallic behavior. Furthermore, we also found that all materials have integral magnetic moments which are mainly due to 100% spin polarization at Fermi energy. The calculated elastic constants and the anisotropy shear factors indicate that these compounds have a ductile character and are mechanically stable. Finally, we calculated the thermoelectric properties by applying Boltzmann theory as implemented in the BoltzTraP code. The results obtained for the merit factor (ZT) and Seebeck coefficient (S) make these materials promising candidates in thermoelectric applications and in spintronics devices. • Investigation of optoelectronic and thermoelectric properties for CO 2 ZrZ (Z = Al, Si, Ga and Sn) using Wien2k code. • Heusler alloys with indirect band gap and a half-metallic behavior. • The studied compounds have a ductile character and stable mechanically. • High electrical conductivity and a figure of merit which is close to unity at low temperatures. • They can be considered as a source of low-temperature energy to produce electricity. [ABSTRACT FROM AUTHOR]

The simultaneous existence of magnetic order and semiconducting nature in ferromagnetic semiconductors fascinate the spintronics technology to enhance the quantum computing and spin transistors. Therefore, electrons spin dependent ferromagnetism and thermoelectric properties of MgCr 2 X 4 (X ​= ​S, Se) spinels are scrutinized by density functional theory (DFT) based Wien2k code. The negative formation energy ensures thermodynamic stability. The band structures (BS) and density of states (DOS) ensure the ferromagnetic semiconductors nature of the studied spinel's. The insulating behavior in down spin and magnetic moment (Integer value) is the response of 100% spin polarization. The fulfillment of the condition Δ (d) > (Δ C F) and negative Δ (p d) have showed the dominant role of electrons spin to induce ferromagnetism. Moreover, influence of electrons spin on thermodynamic and thermoelectric characteristics are explored by specific heat capacity (C v), electrical conductivity (σ/τ), thermal conductivity ((κ/τ)), Seebeck coefficient (S) and power factor (σS2) by classical Boltzmann transport theory. The Ferromagnetic Semiconducting behavior of MgCr 2 X 4 (X ​= ​S, Se) in which up spin channel is semiconducting and down spin channel is insulating. Image 1 • The MgCr 2 X 4 (X ​= ​S, Se) spinels are ferromagnetic semiconductors with 100% spin polarization. • The exchange energies are exactly according to double exchange mechanism. • The above room temperature ferromagnetism enhance the potential for spintronics. • The thermal conductivity and electrical conductivity ratio is of the order of 10−5. [ABSTRACT FROM AUTHOR]