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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]

Mechanical, spin-polarized electronic, and transport characteristics of rare-earth-based MgSm 2 Y 4 (Y S, Se) spinels are investigated using first-principle calculations. In contrast to the anti-ferromagnetic and nonmagnetic states of MgSm 2 Y 4 (Y S, Se), the optimization study reveals that ferromagnetic states release more energy, and optimized lattice constants in ferromagnetic states are comparable to existing values. Phonon dispersion and formation energy are also calculated to confirm the dynamical stability stability. The ductile character is confirmed by investigating the Poisson's and Pugh ratios, and the values of other elastic parameters show their importance for the manufacturing of devices. Heisenberg model and the density of electron states at the Fermi level report the Curie temperature and the spin polarization. Spin-polarized electronic properties indicate half-metallic ferromagnetic because the spin-down reflects a semiconductor nature, whereas the metallic nature manifests the spin-up. The total magnetic moments are generated through hybridization of chalcogenide 2p-states and the Sm f-states. We found that the studied spinels may be used in thermoelectric devices by examining transport characteristics such as electronic and phononic thermal conductivity, Seebeck co-efficient, and figures of merit (ZT). Our results indicate that the ZT for MgSm 2 S 4 is almost three times the ZT obtained for MgSm 2 Se 4. • Half-metallic ferromagentic spinels MgSm 2 Y 4 (Y S, Se). • Phonon dispersion are investigated for dynamical stability. • Electronic and magnetic properties for spintronic applications. • Magnetic moments are discussed for both spinels. • The ZT for MgSm 2 S 4 is almost three times the ZT obtained for MgSm 2 Se 4. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the physical aspects of the cubic phase XCrO 3 (X = Ca , Sr , Ba) perovskites are studied by employing full-potential linearized augmented plane wave plus local orbital (FP-LAPW + lo) method. These compounds have been found stable in ferromagnetic (FM) phase since they possess lower energy in FM phase compared to non-FM phase and their stability is also confirmed by calculating the enthalpy of formation (ΔH). The electronic structures of these compounds are analyzed with Trans and Blaha modified Becke–Johnson potential (TB-mBJ) for both spin up and spin down channels, which indicate their half-metallic characters. Analysis of density of states (DOS) shows major contributions of O-2 p states in the valence band and Cr 3 d -state in conduction band. A comparative analysis of crystal field effect (Δ E crystal) and the exchange energies (direct Δ x (d) and indirect Δ x (p d)) tells about the main part of electronic spin in ferromagnetic character. The calculated magnetic moments make these compounds favorable for spintronic applications. In the end, thermoelectric parameters are computed for 200 K–800 K temperature range to explore potential of these compounds for applications in renewable energy devices. Highlights • To elucidate the structural, electronic, magnetic and thermoelectric properties of cubic XCrO 3 (X = Ca , Sr , Ba) oxides. • We investigate magnetic properties by computing the Δ E crystal , Δ x (d) direct and indirect Δ x (p d) energies. • Thermoelectric properties of spinel oxides have been computed by using BoltzTraP code. • Finally scrutinize that these materials are used in the thermoelectric device. [ABSTRACT FROM AUTHOR]

In this study, we report the mechanical, structural, electronic, magnetic and optical behaviors in Zn 1−x Mn x S (0 ≤ x ≤ 1), which are determined by employing Wein2K code. The ferromagnetic (FM) state stability of the Zn 1−x Mn x S alloys has been elucidated from the calculated values of enthalpy of formation. The elastic constant (C 11 , C 12 , C 14 ) are calculated to find various useful mechanical parameters, which depend upon Mn concentrations. The calculated electronic band structure and density of states (DOS) have demonstrated that exchange splitting through p-d hybridization, arising due to Mn impurities, stabilize a ferromagnetic state. The exchange splitting of the bands is further elucidated from the sharing of magnetic moment, charge and spin, between the impurity cations and the host lattice anions. Various parameters like direct spin-exchange splitting Δ x ( d ), exchange constants N 0 α and N 0 β have also confirmed a stable ferromagnetic state. Various calculated optical parameters have indicated that the studied compounds respond to visible and ultraviolet energies. Moreover, the calculated optical band gap and static dielectric constant ɛ 1 (0) verify Penn's model. The studied compounds of Zn 1−x Mn x S have been shown theoretically that they find potential spintronic and optical device applications. [ABSTRACT FROM AUTHOR]

The full-potential linear-augmented-plane-waves plus local-orbitals (FP-LAPW+lo) method has been employed for investigation of half-metallic ferromagnetism in Cr-doped ordered zinc-blende MgSe and MgTe semiconductors. Calculations of exchange and correlation (XC) effects have been carried out using generalized gradient approximation (GGA) and orbital independent modified Becke–Johnson potential coupled with local (spin) density approximation (mBJLDA). The thermodynamic stability of the compounds and their preferred magnetic orders have been analyzed in terms of the heat of formation and minimum total energy difference in ferromagnetic (FM) and anti-ferromagnetic (AFM) ordering, respectively. Calculated electronic properties reveal that the Cr-doping induces ferromagnetism in MgSe and MgTe which gives rise to a half-metallic (HM) gap at Fermi level ( E F ). Further, the electronic band structure is discussed in terms of s ( p )– d exchange constants that are consistent with typical magneto-optical experiment and the behavior of charge spin densities is presented for understanding the bonding nature. Our results demonstrate that the higher effective potential for the spin-down case is responsible for p–d exchange splitting. Total magnetic moment (mainly due to Cr- d states) of these compounds is 4 µ B . Importantly, the electronic properties and HM gap obtained using mBJLDA show remarkable improvement as compared to the results obtained using standard GGA functional. [ABSTRACT FROM AUTHOR]

Abstract: Structural, electronic and magnetic properties of Mn-doped BeSe and BeTe have been studied by employing the full-potential linear augmented plane waves plus local orbitals (FP-LAPW+lo) method within the spin-polarized density functional theory (DFT). The investigations are carried out by varying the Mn concentration, “x”, in BeSe and BeTe host matrices for x=0.25, 0.5 and 0.75. The results of spin-polarized calculations manifest the presence of ferromagnetic band structures with both spin-up and spin-down alignments. Our calculated results of band structures reveal that for x=0.25, 0.5 and 0.75, Be1−x Mn x Se has a half-metallic (HM) band structure profile showing 100% spin polarization at the Fermi level. On the other hand, the Be1−x Mn x Te band structure shows complete 100% spin polarization at the Fermi level only for x=0.25 and 0.5. Spin-dependent charge densities have been calculated to study the bonding nature, and the values of the exchange constants, and , are also determined which are consistent with the values from the typical magneto-optical experiment. In addition, the calculations of spin exchange splitting, , exhibit important indication regarding the attractive effective potential for minority spin rather than majority spin. For each concentration x, the value of total magnetic moment has been estimated to be 5 , which reveals that addition of Mn impurity does not affect the hole concentration of a perfect BeSe (Te) crystal. [Copyright &y& Elsevier]

Abstract: Density functional FP-LAPW+lo calculations have been performed to study the structural, electronic and magnetic properties of Mg1−x Mn x Te for compositional parameter x =0.25, 0.50, 0.75 and 1. Our calculations reveal the occurrence of ferromagnetism in these compounds in which the transition-metal atom is ordered in a periodical way thereby interacting directly with the host atoms. Results extracted from electronic band structure and density of states (DOS) of these alloys show the existence of direct energy band gap for both majority- and minority-spin cases, while the total energy calculations confirm the stability of ferromagnetic state as compared to anti-ferromagnetic state. The total magnetic moment for Mg1−x Mn x Te for each composition is found to be approximately 5μB, which indicates that the addition of Mn content does not affect the hole carrier concentration of the perfect MgTe compound. Moreover, the s–d exchange constant (N 0 α) and p–d exchange constant (N 0 β) are also calculated which are in accordance with a typical magneto-optical experiment. The estimated spin-exchange splitting energies originated by Mn 3d states energies, i.e. Δ X (s–d) and Δ X (p–d), show that the effective potential for minority-spin is more attractive than that of the majority-spin. Also, the p–d hybridization is found to cause the reduction of local magnetic moment of Mn and produce small local magnetic moments on the nonmagnetic Mg and Te sites. [Copyright &y& Elsevier]

Abstract: We report a systematic study of the structural, electronic and magnetic properties of Cr-doped CdTe for various Cr concentrations x (=0.25, 0.5, 0.75 and 1.0) using first principles calculations based on the density functional theory (DFT). The electronic band structure of the alloy has been calculated using the Wu–Cohen (WC) as well as the Angel-Vosko (EV) generalized gradient approximation (GGA) for the exchange-correlation potential. The analysis of the density of states (DOS) curves shows the half-metallic ferromagnetic character with half-metallic gap more than 0.52eV. While the origin of half-metallic ferromagnetism is explained, the band structure calculations are used to determine s (p)–d exchange constants N 0 α (conduction band) and N 0 β (valence band) that agree with typical magneto-optical experiment. It is found that the p–d hybridization reduces the magnetic moment of Cr from its free space charge value and produces small magnetic moments on the Cd and Te sites. Lastly, we discuss the robustness of half-metallicity with respect to the variation of lattice constants of the Cr x Cd1−x Te alloys. [Copyright &y& Elsevier]

• Spin dependent DFT calculations are executed for MgPr 2 X 4 (X = S, Se). • Structural investigation represent FM stability of MgPr 2 X 4 (X = S, Se). • The band structures analysis show their FM nature of MgPr 2 X 4 (X = S, Se). • The computed optical parameters indicate potential opto-electronic devices applications. • Electronic thermal coefficients are probed and suggested studied spinels as promising sustainable energy materials. In this paper, density functional theory (DFT) calculations are performed to investigate the spin-dependent mechanical, electronic, magnetic, optical, and thermal transport properties of rare-earth-based chalcogenides MgPr 2 X 4 (X = S, Se) spinels. The mechanical properties are obtained by employing the modified Perdew-Burke-Ernzerhof generalized gradient approximation (PBEsol GGA). Also, the modified Becke and Johnson (mBJ) potential is engaged in examining the electronic, magnetic, optical, and transport properties. Structural stability in the ferromagnetic (FM) phase is confirmed by calculating the energy difference between the FM and non-magnetic states. Besides, the formation energies are computed for thermodynamic stability. The strong hybridization near the Fermi level comes from chalcogenides 2p-states and f-states of rare-earth metals, which results in the total magnetic moments. The in-depth optical properties are evaluated in terms of dielectric constant and refraction. Lastly, electronic thermal coefficients, such as Seebeck coefficient, electrical and thermal conductivity, and power factor, are also probed and suggested studied spinels as promising sustainable energy materials. [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]

Abstract: For investigating the structural, electronic and magnetic properties of zincblende (ZB) Cd1−x V x Te (0≤x≤1), we have employed the Wu–Cohen generalized gradient approximation (WC-GGA) and the modified Becke and Johnson local density approximation (mBJLDA) functionals within the frame-work of spin polarized density functional theory (DFT). The former exchange-correlation parameterization scheme has been used for optimizing the equilibrium structural properties, while the electronic band structures, electron density of states (DOS) and charge densities are computed using both functionals and their performances are compared. Our results show that the electron spin polarization in unfilled V-3d orbitals gives rise to spin exchange splittings (Δ x (d) and Δ x (pd)) which is the cause of half metallic (HM) ferromagnetism in the V-doped CdTe as revealed by the computed DOS. Consequently, the nature of effective potential is more attractive in spin-down case rather than that in spin-up case. The total magnetic moment for each of the compounds under study is 3μB where the main contribution comes from the V atom, while the nonmagnetic sites Cd and Te are also bestowed with minor atomic magnetic moments due to Te-5p–V-3d hybridization. Furthermore, we calculated the exchange constants N 0 α and N 0 β to determine the conduction and valence band contributions in exchange splitting process. A comparison of the two functionals, considered in this work, shows that the mBJLDA provides a better description of the electronic structure especially of the ferromagnetic Cd1−x V x Te (0.75≤x≤1). Moreover, as compared to WC-GGA, the mBJLDA predicts high Curie temperatures in V-doped CdTe by providing significantly larger values of Δ x (d), Δ x (pd), N 0 α, N 0 β and, importantly, a quite wide HM gap. [Copyright &y& Elsevier]

Abstract: We systematically explore Cr-doped zinc blende BeSe and BeTe compounds in terms of their structural, electronic and magnetic properties by using the first-principles full-potential linearized augmented plane waves plus local orbitals (FP-LAPW + lo) method. The state stability of the doped materials has been studied by calculating the heat of formation and analysing minimum total energies in ferromagnetic (FM) and anti-ferromagnetic (AFM) coupling. A non linear dependency of Cr concentration on the lattice parameters and bulk modulus is found which shows small deviation from Vegard''s law. Our calculations for each Cr concentration were performed using two different density functional theory functionals which are the Wu and Cohen (WC) and the modified Becke and Johnson local (spin) density approximation (mBJLDA). The functionals generate spin dependent band structures, electronic density of state (DOS) and magnetic moments that exhibit occurrence of half-metallic ferromagnetism which is caused by spin polarization of electron in Cr-d orbitals. Importantly, comparison between the two functionals shows that the mBJLDA functional provides a better description of the electronic structure of the Cr-doped binary systems. The calculated exchange interaction and exchange constant, N 0 α and N 0 β, respectively, are consistent with the values from typical magneto-optical experiment and conversely, the calculated charge spin densities allowed us to understand the bonding nature. In addition, the calculations of spin exchange splitting, Δ x (d), exhibit important indication regarding the attractive effective potential for minority spin rather than majority spin. [Copyright &y& Elsevier]

The structural, electronic and magnetic properties of Cr-based MgSe in zinc blende phase have been investigated by employing the full-potential linear augmented plane waves plus local orbitals (FP-LAPW+lo) method within the spin-polarized density functional theory (DFT). According to our findings, Mg 1− x Cr x Se exhibits a half-metallic characteristic, where the ferromagnetic state is more favorable than the antiferromagnetic state. The band structure results of half-metallic Mg 1− x Cr x Se system for x =0.25, 0.50 and 0.75 show 100% spin-polarization at the Fermi level ( E F ). The total magnetic moment is 4 μ B which is mainly due to the Cr-3 d states at the Fermi level ( E F ). Our results indicate the presence of small magnetic moments arising from the other non-magnetic atoms as well. We also calculated the spin dependent charge densities to understand the bonding nature of the system. [ABSTRACT FROM AUTHOR]

Ab-initio calculations for V-doped BeSe and BeTe semiconductors are performed by means of all-electrons full-potential linearized augmented plane wave plus local orbital (FP-LAPW+lo) method. The structural properties are optimized using the Wu-Cohen generalized gradient approximation functional, whereas modified Becke and Jhonson local density approximation functional has been employed for evaluating the spin-polarized electronic and magnetic properties. Magnetic stability at various doping concentrations in ferromagnetic (FM) and anti-ferromagnetic (AFM) ordering is investigated by comparing the minimum total energies and enthalpies of formation (Δ H ). Studied band structures, density of states, total energy, exchange interactions and magnetic moments manifest both alloys with half-metallic ferromagnetic behavior. Moreover, their valance bands are found to be paired ferromagnetically with V atoms. Furthermore, it was observed that the magnetic moment of vanadium atom reduces from free space charge value due to p–d hybridization which yields small magnetic moments on the Be, Se and Te sites. [ABSTRACT FROM AUTHOR]