Half-metallic Ferromagnetic Behavior Research Articles

Structural, electronic and elastic properties of FeCrAs Half-metallic ferromagnetic Half-Heusler Alloy: A First-Principles study

In this work, we employ full potential linearized augmented plane wave approach based on the density functional theory to calculate the structural, electronic, and elastic properties of FeCrAs Half-Heusler compound. For electron exchange, we have considered the most common Generalized Gradient Approximation (PBE-GGA and PBEsol-GGA), as exchange and correlation potential for investigating these properties. The half-metallic ferromagnetic behavior is confirmed by density of states and spin-polarized band structures analysis, which show that the FeCrAs has an indirect band-gap in the spin-down channel and a metallic behaviour in the spin-up channel. Furthermore, the elastic constants (Cij) and the related elastic moduli confirm their stability in the cubic phase and demonstrate their brittle nature. The Debye’s temperature along with compressional, Shear and average elastic wave velocities has also been calculated.[copyright information to be updated in production process]

Electronic and magnetic behaviors of (V, Mn), (V, Fe) and (V, Cu) codoped tin carbide: Ab initio and Monte Carlo calculations

In the present study, we performed ab initio calculations for tin carbide codoped with (V,Mn), (V,Cu) and (V,Fe). The electronic and magnetic properties of tin carbide are calculated by means of density functional theory (DFT). The half metallic ferromagnetic behaviour of dual impurities VMnSnC, VFeSnC and VCuSnC is treated by using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA). Our results evince that, the stability of ferromagnetism state was induced by the charge state of magnetic impurities, which room temperature ferromagnetic DMS based spintonic is realized. The exchange interactions are obtained from first principles calculations using an Ising model. Our calculation is supported by Monte Carlo simulation based on the heat bath algorithm. We have examined the effects of magnetic parameters for magnetization, internal energy and magnetic susceptibility.

Half Metallic Ferromagnetism and Transport Properties of Zinc Chalcogenides ZnX2Se4 (X = Ti, V, Cr) for Spintronic Applications.

In ferromagnetic semiconductors, the coupling of magnetic ordering with semiconductor character accelerates the quantum computing. The structural stability, Curie temperature (Tc), spin polarization, half magnetic ferromagnetism and transport properties of ZnX2Se4 (X = Ti, V, Cr) chalcogenides for spintronic and thermoelectric applications are studied here by density functional theory (DFT). The highest value of Tc is perceived for ZnCr2Se4. The band structures in both spin channels confirmed half metallic ferromagnetic behavior, which is approved by integer magnetic moments (2, 3, 4) μB of Ti, V and Cr based spinels. The HM behavior is further measured by computing crystal field energy crystal, exchange energies x(d), x (pd) and exchange constants (No and No). The thermoelectric properties are addressed in terms of electrical conductivity, thermal conductivity, Seebeck coefficient and power factor in within a temperature range 0–400 K. The positive Seebeck coefficient shows p-type character and the PF is highest for ZnTi2Se4 (1.2 × 1011 W/mK2) among studied compounds.

A study via density functional theory calculations of transition metal diselenide monolayers

In this paper, the physical properties such as structural, electronic, and magnetic of vanadium diselenide, chromium diselenide, molybdenum diselenide and tungsten diselenide monolayers were studied. The calculations were performed in the hexagonal structure (1H) and using the density functional theory. The computational calculation shows that the exfoliation energies of four monolayers are 18.92 meV/Å2, 19.83 meV/Å2, 22.42 meV/Å2, and 33.85 meV/Å2, respectively. While the formation energies values per atom were −2.88 eV, −2.47 eV, −3.31 eV, and −.398 eV, respectively. The monolayers are thermodynamically stable because the formation energies are negatives. Finally, the band structure study reveals that vanadium diselenide monolayer have a half-metallic ferromagnetic behavior, while the chromium diselenide, molybdenum diselenide and tungsten diselenide monolayers present a direct semiconductor character. Due to these properties the monolayers have potential application in micro, nano electronics, and spintronic devices.

DFT study, Mean-Field Approximation and Monte-Carlo simulation of physical properties of Fe and Cr doped and co-doped GaN

The present study is carried out for investigating the half-metallic ferromagnetic behavior of Cr and Fe doped and co-doped GaN, respectively. To this end, ab-initio calculations using the Korringa-Kohn-Rostoker Green's function method coupled with the coherent potential approximation have been employed. In the background to make the study more useful, the first-principles computations were added and merged to the mean-field approximation and the Monte-Carlo simulation for the co-doped compound. Several variations were perceived in the results as in the bandgap energy, the energetic location of the transition-metal 3d band and the X-ray absorption spectra. Besides, the stability of the system between the ferromagnetic and the spin-glass states is studied. Finally, we have integrated as input parameters in the classical Ising model by Monte-Carlo simulation, the exchange interactions obtained from ab-initio calculation, in order to confirm the half-metallic ferromagnetic states with high Néel temperature.

Physical characteristics of barium based cubic perovskites

The full potential linearized augmented plan wave method (FP-LAPW) within density functional theory (DFT) is applied to examine the structural, electronic, magnetic and optical characteristic of barium based perovskitesBaXO3(X = Th, U) in cubic phase. BaThO3 and BaUO3compounds are stable in the non-magnetic and ferromagnetic ground states, respectively. The BaUO3compound showed the half metallic ferromagnetic (HMF) behavior, while BaThO3 revealed the insulating behavior with a band gap (Eg) of 3.16 eV. The spin down region has a Eg of 3.39 eV and spin up channel shows the metallic character for BaUO3 compound. The dielectric function ɛ (ω), extinction coefficient k (ω), refractive index n (ω), reflectivity R (ω), optical absorption α (ω) are also calculated. Results indicate that BaUO3 is useful for spintronics and optoelectronic devices whereas both compounds are suggested to be suitable for optoelectronic application.

First-principles calculations to investigate electronic structure and magnetic, mechanical and thermodynamic properties of d0 half-Heusler LiXN (X= Na, K, Rb) alloys

Density functional theory (DFT) incorporating GGA-PBE approximation has been implemented to study structural, electronic, magnetic, mechanical and thermodynamic properties of the d0 Half-Heusler LiXN (X = Na, K, Rb) alloys. According to the spin-polarized calculations, all the LiXN alloys crystallize in the α-phase ferromagnetic ground state configuration. All three LiXN alloys show a total magnetic moment of 1.00 μB. The integer values of the total magnetic moments, along with the spin-polarized electronic band structures and the density of states plots indicate that the LiXN alloys are true half-metals in nature. The half-metallic nature of the LiXN alloys is further confirmed as the total magnetic moments are in complete agreement with the Slater-Pauling rule of 8. The origin of the half-metallic ferromagnetic behaviour has been investigated and it has been observed that the 2p states of N are the major contributors in case of all the three alloys. The alloys retain the characteristic half-metallicity over a wide range of lattice parameters, thus confirming their robustness and usability in a variety of spintronic applications. The mechanical properties of the LiXN alloys have been investigated and it has been observed that LiKN and LiRbN are found to be mechanically unstable, whereas LiNaN is chemically, energetically and mechanically stable. Various thermodynamic properties have been further computed and analysed using the quasi-harmonic approximation (QHA). Specific heat capacity at room temperature (300K), the Debye temperature, and the zero-point energy for the LiNaN alloy as well as the average velocity of sound inside the LiNaN alloy have been evaluated.

Comparative study of half-metallic ferromagnetic behaviour in ZnO monolayer doped with boron and carbon atoms

Electronic band structures of B- and C-doped ZnO monolayers (ML) at high doping concentration are studied based on spin-polarized plane-wave DFT with Projector Augmented Wave Potentials and Generalized Gradient Approximation. Our results show that both the B- and C-doped structures at 3.13% impurity atom per supercell exhibit half-metallic ferromagnetic behaviour due to the spin-polarized 2p orbitals of the dopant atom, which are localized within the energy gap of the host lattice. A net magnetic moment of 1μB and 2μB are, respectively, found in the B- and C-doped structures mainly due to the partially filled dopant atom 2 p orbitals. Due to ferromagnetic coupling, magnetic moments from the neighbouring Zn atoms and the subsequent O atoms also contribute to the net magnetic moment. At a higher doping concentration of 6.25% impurity atom per supercell, both the materials completely transformed into metal. It is also found that while C doping maintains its ferromagnetic property at this doping concentration, the B-doped ZnO ML becomes antiferromagnetic metal. Our findings would provide valuable theoretical data for material scientists in fabrication of the doped ZnO ML in laboratory

Strain induced electronic structure, and magnetic and structural properties in quaternary Heusler alloys ZrRhTiZ (Z = Al, In)

Electronic structure, and magnetic and structural properties of quaternary Heusler alloys ZrRhTiZ (Z = Al, In) have been analyzed from first principles calculations. The ferromagnetic ground state and thermodynamical stability of these compounds are supported by relative total energies, and by derived formation and cohesive energies, respectively. The investigated Curie temperatures of the compounds exceed room temperature indicating that these compounds are promising candidates for beyond room temperature spintronics and magneto-electronics applications. Both compounds follow the Slater-Pauling 18 electron rule and exhibit half-metallic ferromagnetic behavior with magnetic moments of 2 μB with 100% spin polarization in one spin channel at the Fermi-level. The effect of uniform strain on half-metallicity of these compounds inverts the band gap from one spin channel to another spin channel with a mixed spin (magnetic moment) regime that can be mapped to an exchange bias like effect observed in some of the magnetic Heusler compounds. The half metallic ferromagnetic behavior is retained within −2 to 2% strain contrasting with the anomalous spin flip in −1% and 1% strain in ZrRhTiZ (Z = Al, In).

A Theoretical Analysis of Physical Properties and Half-Metallic Stability under Pressure Effect of the ScNiCrZ (Z=Ga, Al, In) Heusler Alloys

The aim purpose of this study is to investigate the structural, elastic, magnetic, electronic properties and half-metallic stability under pressure of ScNiCrZ ([Formula: see text], Ga and In) quaternary Heusler alloys using full-potential linear muffin-tin orbital (FP-LMTO) method within the gradient generalized approximation (GGA) for exchange, and correlation potential. In order to evaluate the stability of our compounds, the formation energy, and elastic constants have been evaluated. The results showed that our compounds have ferromagnetic ground states and are energetically more stable in type-[Formula: see text] configuration. True half-metallic ferromagnetic behavior with 100% spin polarization at Fermi level [Formula: see text] with high Curie temperature [Formula: see text], and very interesting bandgap in the minority spin are obtained for the three alloys. The calculated total magnetic moment [Formula: see text] for all three alloys is consistent with Slater[Formula: see text]Pauling rule. The half-metallicity is maintained over a wide range of lattice constants making these alloys promising for spintronic, and magneto-electronics applications.

Study of Half Metallic Ferromagnetism and Optical Properties of Mn-Doped CdS

The spin-polarized electronic band structures, density of states and optical and magnetic properties of dilute magnetic semiconductors (DMSs) Cd1−xMnxS with 6.25%, 12.5% and 25% concentrations of Mn have been studied by using ab initio calculations. The electronic band structures show half metallic ferromagnetic (HMF) behaviour with direct band gap at Γ symmetry point. The calculated values of band gaps are 0.8 eV, 0.99 eV, 1.3 eV and 1.5 eV for CdS, Cd0.9375Mn0.0625S, Cd0.875Mn0.1250S and Cd0.75Mn0.25S, respectively. The energy gap of CdS was found to increase by doping with transition metal impurity. The addition of the dopant atoms in CdS turns it into a p-type semiconductor. This half metallic character makes these compounds a potential candidate for spintronics applications. In optical properties, the role of Mn concentration on the absorption coefficient, optical conductivity, refractive index, extinction coefficient and dielectric function has been investigated. The total magnetic moment is found approximately 5.000 μB per dopant atom for Cd1−xMnxS (x = 6.25%, 12.5% and 25%). This value indicates that every Mn impurity adds no hole carriers to the perfect CdS crystal.

DFT study of structural, electronic, elastic and magnetic properties of In0.75Cr0.25P

The theoretical calculations of structural, electronic, elastic and magnetic properties of In0.75Cr0.25P Diluted Magnetic Semiconductor (DMS) in Zinc Blende phase (B3) has been performed using Density Functional Theory (DFT) as implemented in the Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA) code with LDA + U (U = 3) exchange–correlation (XC) potential. The study of spin polarized electronic band structures and magnetic properties represents the induction of half metallic ferromagnetic behaviour in In0.75Cr0.25P with 100% spin polarization. Different types of elastic parameters of ternary alloy have been calculated and results confirm that this compound is stable and predicts its anisotropic and ductile nature. The hybridization of Cr-3d states with s and p states of In and P develops some local magnetic moment on non magnetic In and P atoms. The calculated results of different properties are compared with available literature data and are in good agreement.

Ab-initio study of the structural, electronic and magnetic properties of double-perovskite Sr2BUO6 (B = Mn, Ni, and Zn) compounds

We present a systematic study of the structural, electronic and magnetic properties for double-perovskite Sr2BUO6 (B = Mn, Ni, and Zn) compounds using density functional theory via Full-Potential Linearized-Augmented-Plane-Wave approach (FP-LAPW). We calculated lattice constants; partial and total spin polarized density of states in addition to charge density. Our structural study shows that the compounds have cubic symmetry. A half metallic ferromagnetic behavior is found in Sr2MnUO6 which can be promising in spintronic applications, while both of Sr2NiUO6 and Sr2ZnUO6 showed a semi-conducting behavior; our investigation also manifested the nonmagnetic behavior of Sr2ZnUO6, as expected.

Electronic, optical and magnetic properties of low concentration Ni-doped CdSe by first principle method

The electronic, magnetic and optical properties of Ni-doped CdSe diluted magnetic semiconductors have been explored by density functional theory-based FPLAPW method as incorporated in the Wien2k code. The band structure and density of states analysis for up spin channel and down spin channel illustrate half-metallic ferromagnetic behaviour. The calculated values of the band gap in an insulating channel (down spin channel) increases from 0.4 to 0.8 eV with increasing the doping concentration of Ni from 6.25 to 25%. The magnetic moment of Ni decreases and magnetic moment on nonmagnetic side increases, which shows the strong pd-hybridization. Furthermore, the optical properties are characterized in terms of dielectric constants, refractive index, extinction coefficient, absorption coefficient and optical loss factor. The static values of the dielectric constant and refractive index are consistent with each other.

Half-metallic ferromagnetic behavior of cubic lanthanide based on perovskite-type oxide NdCrO3: first-principles calculations

In this study, theoretical investigation on structural, electronic and magnetic properties of the cubic perovskite oxide NdCrO3 has been performed within density functional theory. The exchange and correlation potential is treated by three approximations: generalized gradient approach of Perdew, Burke and Ernzerhof (GGA–PBE), GGA plus band correlated Hubbard parameter (GGA + U) scheme and GGA plus Tran–Blaha-modified Becke–Johnson (TB-mBJ–GGA) approximation which has been used to describe the energy band gap more accurately. Structural results found in the course of this study are in perfect agreement with experimental measurements and show that the ground state of the studied compound is ferromagnetic. The electronic band structures and density of states display a half-metallic behavior of the cubic perovskite NdCrO3 with an indirect band gap in minority spin. The magnetic study shows that the total magnetic moment of 6 μB mainly originates from the both atoms Nd and Cr. The integer value confirms a half-metallic nature of the studied material. Consequently, the NdCrO3 is a promising candidate for the useful spintronic applications.

New stable half-metallic ferromagnetic structure of KO

ABSTRACTThe study of the structural, mechanical, magneto-electronic properties and Half-Metallic Ferromagnetic behavior of KO material in the CsCl structure, are reported using the Full Potential Linearized Augmented Plane Wave method with the Generalized Gradient Approximation of Perdew–Burke–Ernzerhof for the exchange–correlation term. The findings show that KO is energetically more stable in the ferromagnetic phase of the CsCl-structure than of zincblende and rocksalt structures. The calculated elastic constants reveal that KO is mechanically stable with ductile character. The computed pressure transition from the ambient structure Cmca to the CsCl-structure is 45.7 GPa. From the electronic properties, KO is half-metallic. The total magnetic moment, the gap in the spin-up channel and HM gap values are respectively equal to 1 μB, 6.09 and 1.05 eV. Finally, the HMF-character is maintained up to 167 GPa. These results show that KO in the CsCl structure might have potential spintronic applications in the future.

Improved Electronic Properties with New Half-Metallic Ferromagnetic Behavior of ZnCrO2 and ZnMnO2 from TB-mBJ Exchange Potential

Improved Electronic Properties with New Half-Metallic Ferromagnetic Behavior of ZnCrO₂ and ZnMnO₂ from TB-mBJ Exchange Potential

The effect of substitution of Cr impurities at the In sites on the structural, electronic and magnetic properties of InSb: a DFT study within mBJ potential

In this work, we have investigated the structural, electronic and magnetic properties of In1 − xCrxSb alloys in zinc blende at concentrations x = 0.125, 0.25, 0.50, 0.75, 0.875 and 1. We have performed our calculations by the use of first-principle methods based on spin-polarized density functional theory, where the electronic exchange–correlation potential is treated by the generalized gradient approximation GGA-WC and the improved TB-mBJ approach. The calculated structural parameters of InSb are in good agreement with the available theoretical and experimental data. The ternary In1 − xCrxSb alloys show half-metallic ferromagnetic behavior with a spin polarization of 100% at the Fermi level. The total magnetic moments are 3 μB for all compounds and the interaction is antiferromagnetic between Cr–Sb and Sb–In sites. These materials are half-metallic ferromagnets, and they can be potential candidates for spintronic applications.

Theoretical Investigation of the Electronic Structure and Magnetic Properties in Ferromagnetic Rock-Salt and Zinc Blende Structures of 3d (V)-Doped MgS

In this work, we studied the properties of vanadium doped binary MgS compound Mg1−xVxS (x = 0.125, 0.25, 0.50 and 0.75) in both ferromagnetic rock-salt and zinc-blende structures. The studied properties are structural, electronic and magnetic. The objective of this study is to explore the new dilute magnetic semiconductor systems. We have used two approximations to simulate these properties: Wu–Cohen generalized gradient approximation for structural properties, and the modified Becke–Johnson potential combined with the local density approximation for electronic and magnetic properties. The general context in which the calculations are done is based on the formalism of the spin-polarized density functional theory and the full-potential linear-augmented plane wave method. Among the various compounds studied, we have identified a ferromagnetic semiconducting behavior in the rock-salt structure. In the zinc-blende structure, we have one metallic candidate consisting of 75% V-doping of the Mg-sublattice, and all other compounds have a half-metallic ferromagnetic behavior. We conclude that the Mg1−xVxS compounds, for x = 0.125, 0.25 and 0.50, in the zinc-blende structure are a diluted magnetic semi-conductors materials. To see the effects of the exchange splitting process, the exchange constants N0α and N0β are calculated. For each concentration x, we have found the values of the total magnetic moment equal to 3 μβ excepted for the case of Mg0.25 V0.75S compound in the zinc-blende structure. The value of the total magnetic moment is due principally to V magnetic atom and to other both nonmagnetic atoms Mg and S, which show small local magnetic moments localized on their sites. The presence of ferromagnetic order in this type of compound can be explained by the p-d hybridization phenomena.

Half metallic ferromagnetic behavior in (Ga, Cr)N and (Ga, Cr, V)N compounds for spintronic technologies: Ab initio and Monte Carlo methods

Abstract In this article, we investigate the magnetic and electronic properties of GaN doped with simple and double impurities utilizing Ab initio and Monte Carlo studies. We have predicted that (Ga, Cr)N and (Ga, Cr, V)N compounds exhibit ferromagnetic- and halfmetallic-behavior with 100% spin polarization at the Fermi level. Moreover, we have found that Ga1−xCrxN and Ga1−2xCrxVxN (x = 0.04, 0.05 and 0.06) show a second order ferromagnetic transition and that their Tc is above room temperature. These predictions make (Ga, Cr)N and (Ga, Cr, V)N compounds strong candidates for spintronic technologies.