Half-metallic Ferromagnetic Character Research Articles

Study of half-metallic ferromagnetism and transport characteristics of double perovskites Sr2AIrO6 (A = Y, Lu, Sc) for spintronic applications.

The precise manipulation of electromagnetic and thermoelectric characteristics in the miniaturization of electronic devices offers a promising foundation for practical applications in quantum computing. Double perovskites characterized by stability, non-toxicity, and spin polarization, have emerged as appealing candidates for spintronic applications. This study explores the theoretical elucidation of the influence of iridium's 5d electrons on the magnetic characteristics of Sr2AIrO6 (A = Y, Lu, Sc) with WIEN2k code. The determined formation energies confirm the thermodynamic stability while an analysis of band structure and the density of states (DOS) reveals a half-metallic ferromagnetic character. This characteristic is comprehensible through the analysis of exchange constants and exchange energies. The current analysis suggests that crystal field effects, a fundamental hybridization process and exchange energies contribute to the emergence of ferromagnetism due to electron-spin interactions. Finally, assessments of electrical and thermal conductivities, Seebeck coefficient, power factor, figure of merit and magnetic susceptibility are conducted to assess the potential of the investigated materials for the applications in thermoelectric devices.

Engineering the electromagnetic response and thermoelectric performance of half-functionalized stanene with [formula omitted], [formula omitted], [formula omitted], [formula omitted] and [formula omitted

We report on, for the first time, a combined density functional theory and Boltzmann-semiclassical calculations of two-dimensional stanene half-passivated with X=H,F,Cl,Br and I The thermodynamical stability is examined through the comparison of the formation energy as well as the analysis of the phonon dispersion spectrum indicating a possible experimental fabrication of these stanene derivatives. Interestingly, using generalized gradient approximation (GGA), the obtained results show that half-iodination and half-hydrogenation induce a half metallic ferromagnetic character and the magnetic moment on the unsaturated Sn atoms are 0.41μB and 0.38μB for SnSn–H and SnSn–I respectively, whereas half-decoration with fluorine, chlorine and bromine adsorbates, characterized with high electronegativity, gives rise to antiferromagnetic metallic systems. Except SnSn–I, the critical temperatures of the stanene derivatives are above room temperature. These results suggest that magnetism of stanene can be tuned by different passivation atoms. The transport properties, which result in a thermoelectric figure of merit (ZT), are very sensitive to the doping type however, less affected by the temperature variation. The highest ZT value of 0.99 is recorded for the SnSn–H conformer, while it decreases with the increase of the electronegativity. For the four compounds, the maximum figure of merit and seebeck coefficients are located at n-type doping, suggesting that these materials can be strong candidates among n-type materials for thermoelectric applications in high-temperature regions. Our findings demonstrate that half passivation with X-atoms is a feasible method to tune the properties of stanene for spin injection applications and thermoelectric cooling industry.

Insight into electronic, magnetic and optical properties of KMnxNb1-xO3 compound

Density functional theory (DFT) based calculations are performed to study the physical features of Mn doped KNbO3. The spin resolved electronic band structure (BS) and density of states (DOS) are investigated that confirmed the half-metallic ferromagnetic (HMFM) character at x=12.5 and 25% Mn concentration. The energy gap of pure KNbO3 is found to majority influenced by Mn-3d states which introduces new states in the vicinity of Fermi level. The optical features (dielectric function, absorption coefficient, extinction coefficient, refractive index and optical conductivity) are examined to further reveal the role of Mn doping on the KNbO3 compound for optical devices. Finally in magnetic properties, the total magnetic moment of 2.98 and 3.68 μB which is mainly originated from Mn-3d along with weak contribution from K, Nb, and O. Results revealed that KMnxNb1-xO3 compound is a favorable candidate for optoelectronics and spintronics gadgets applications.

DFT insight into magnetoelectronic and optical properties of Mo-modified BaTiO3

Herein, the magnetoelectronic and optical characteristics of Ba1-xMoxTiO3 (x = 25%, 50%, and 75%) compound are computed by employing density functional theory (DFT). The robust half metallic ferromagnetic (HMF) character has been observed for Mo-incorporated BaTiO3. This behavior of Mo-modified BaTiO3 is due to the highly asymmetric behavior in both spin channels, semiconducting in dn-spin and metallic nature in up-spin version. The computed total magnetic moment (MTot) is found to be 4.0 μB for all substitutional concentrations which is mainly due to the Mo-4d states. In addition, the optical parameters (extinction coefficient, reflectivity, optical conductivity, refractive index, dielectric function, and absorption coefficient) are also calculated. The computed results suggest the suitability of studied material for spintronic and optoelectronic devices.

Tuned physical characteristics of PbSe binary compound: a DFT study

Physical features of transition metal (TM) doped lead selenide, Pb1-xCrxSe, Pb1-xCoxSe and Pb1-xNixSe (x=0% and 25%) have been investigated by ab-inito method. The exchange correlation energy is computed by generalized gradient approximation (GGA). A direct band gap (Eg) of 0.35 eV has been observed for PbSe. The analysis of spin-resolved electronic band structure (BS) and density of states (DOS) reveal the half-metallic ferromagnetic (HMF) character of doped compounds. In addition, the calculated magnetic moments (μB) of Pb1-xCrxSe, Pb1-xCoxSe and Pb1-xNixSe compounds are found to arise due to doped transition metals and confirmed by 3D spin-polaized iso-surface density plots. The optical features including optical conductivity (), absorption coefficient, extinction coefficient k, refractivity R, dielectric function and refractive index n() have been calculated to envisage the optical response of given materials. Further, the BoltzTrap code has been implemented to probe the thermoelectric characteristics in term of power factor (PF), Seebeck coefficient (S), thermal and electrical conductivity. The outcomes of calculations divulge that Pb1-xXxSe (X=Cr, Co, Ni) would be suitable candidates for both optoelectronics and thermoelectric applications.

Persistent half-metallic ferromagnetism in a (111)-oriented manganite superlattice

We employ electronic structure calculations to show that a (111)-oriented (LaMnO3)12∣(SrMnO3)6 superlattice retains a half-metallic ferromagnetic character despite its large thickness. We link this behaviour to the strain and the octahedral connectivity between the layers. This also gives rise to breathing modes, which are coupled to charge and spin oscillations, whose components have a pure eg character. Most interestingly, the magnetisation reaches its maximum value inside the LaMnO3 region and not at the interface, which is fundamentally different from what observed for the (001) orientation. The inter-atomic exchange coupling shows that the magnetic order arises from the double-exchange mechanism, despite competing interactions inside the SrMnO3 region. Finally, the van Vleck distortions and the spin oscillations are crucially affected by the variation of Hund’s exchange and charge doping, which allows us to speculate that our system behaves as a Hund’s metal, creating an interesting connection between manganites and nickelates.

Tuning half metallic ferromagnetic character in Rh and Tc doping Cerium dioxide for spintronic applications

In this paper, we investigate, for the first time, the effect of Rhoduim (Rh) and Technetium (Tc) on the electronic and magnetic properties of the dilute magnetic semiconductor CeO2 using the Korringa-Kohn-Rostoker (KKR) method combined with the generalized gradient approximation (GGA). Three different concentrations (x = 0.05, 0.10, 0.15) are considered. The energy diagram of density of states reveals that the dopant changes CeO2 from a non magnetic semiconductor to ferromagnetic half metals. Furthermore, the energy variation ensures the stability of the ferromagnetic phase due to the double exchange mechanism. The Curie temperature is evaluated and turns out to be above the ambient temperature for the different concentrations. The present findings model new potential candidates for spintronics.

Magnetic and optical characteristics of Fe doped SrTiO3 perovskite compound: a first principle study

In this study, we theoretically probed the electronic, magnetic and optical characteristics of Sr1-xFexTiO3 and SrTi1-xFexO3 perovskite materials with the implementation of DFT based Wein2K code. In both doping atom is partially removed by (Fe) dopant. The substitution of Fe at A-site in SrTiO3 consequences the half-metallic ferromagnetic (FHM) character, while the substitution of Fe at B-site in SrTiO3 resulted into metallic character of the studied material. Moreover, In Sr0.5Fe0.5TiO3 the local magnetic moment of Fe is slightly decreased, whereas in SrTi0.5Fe0.5O3 the Fe magnetic moment is highly decreased from its free space value 4 µB. This reduction is due to p-d hybridization. In case of Sr0.5Fe0.5TiO3, the exchange constants N0α for s-d and N0β for p-d interaction are computed. The optical response of studied materials is described by jn.hat Sr0.5Fe0.5TiO3 is a prominent candidate for spintronics applications.

Magnetic, opto-electronic, and thermodynamic properties of half-metallic double perovskite oxide, Ba2YbTaO6: a density functional theory study

Double perovskite oxide, Ba2YbTaO6 (BYT), has been studied under the realm of DFT-based calculation implemented in Wien2K code. Spin-polarized electronic and magnetic calculations show the 100% spin polarization across the Fermi level and confirm the half-metallic ferromagnetic (HMF) character for the compound. Bandgap (~ 3.47 eV) is calculated using the mBJ exchange correlation and found to be in good agreement with its reported experimental (3.95 eV) value. It has been found that Yb-f orbitals have major contribution in density of states (DOS) near and at Fermi levels. Optical spectra show that static refractive index is more than one (~ 4.5) and well correlated with the Penn Model. Both absorption and optical conductivity spectra show significance for its application in UV-based opto-electronic devices. Our studied electronic, optical, and magnetic properties suggest that material has significance in spintronic and optical devices.

Prediction of the Half Metallicity in Ferromagnetic Germanium Telluride (GeTe) Doped with Titanium

This research work studies the structural, electronic and magnetic properties of Ge[Formula: see text]TixTe (for [Formula: see text], 0.50, 0.75, 1) compounds in rock-salt structure based on first-principles spin-polarized density functional theory. As it is implemented in WIEN2k code, the full-potential augmented plane-wave method was used in the investigation. To evaluate the structural properties of compounds, the exchange-correlation term is estimated using PBE-GGA approximation. For the other properties such as the electronic structures, densities of states and local moments, the generalized gradient approximation PBE-[Formula: see text] is used. The analysis of spin-polarized density of states has shown the half-metallic ferromagnetic character when [Formula: see text] and 0.75; while at [Formula: see text], we obtained near half-metallic behavior. In order to validate the effects resulting from exchange splitting process, we calculated the exchange constants [Formula: see text] and [Formula: see text]. For Ti atomics sites, the value of total magnetic moment has been estimated equal to [Formula: see text] in all studied compounds. We have found that the local magnetic moment of Ti is reduced and small local magnetic moments on nonmagnetic atomics sites of Ge and Te were created by the p-d hybridization effect.

Investigation Insights into Electronic Structures, Exchange Splittings, Induced Ferromagnetism, and Half-Metallic Feature in New Ti-Doped BaS

The new Bai-xTixS compounds based on the titanium (Ti)-doped BaS at various concentrations x = 0.25, 0.5 and 0.75 were characterized using the first-principle concepts of density functional theory. We investigated the doping effect of titanium on the structural and electronic properties, induced ferromagnetism, half-metallicity and exchange splittings in Ba1-xTixS materials. The origin of ferromagnetism in the Ba1-xTixS compounds is due to the localized partially occupied 3d (Ti) states related to the double exchange mechanism. The electronic structures of Ba1-xTixS at concentrations x = 0.25 and 0.5 show half-metallic ferromagnetic character with spin polarization of 100%. For concentration x = 0.75 the Ba0.25Ti0.75S exhibits a metallic nature for two spins channels due to widening 3d (Ti) states in the gap. Therefore, Bai-xTixS at concentrations x = 0.25 and 0.5 seems to be potential candidat for spintronics.

Half-metallicity in [formula omitted] and V doped tin-carbide SnC

Electronic and magnetic properties of V and Mn doping SnC are investigated in this work. The ab-initio structure calculation based on the Korring-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA) have been used. We have found that the substitution of Sn atoms in Tin-Carbide by Mn and V Transition Metals brings a half-metallic ferromagnetic character with a double exchange mechanism. The partial moments of impurities in the compound varies slightly from 1.11 to 1.09 μB in V case and 3.56 to 3.5 μB for Mn case. While the polarization is found to be equal 100%, in both cases where the up-spins channel is conductive, while the down channel is insulating. Using the Vegard's law, we have determined the laticce parameter of the doping compounds as function of the impurities concentrations. Such features has a significant implications for the performance of spintronic instruments and boosts their magnetoresistance ability at an enormous rate. Hence, the critical temperature can be controlled by varying the concentration of impurities.

First-Principle Study of Structural, Elastic, Electronic and Magnetic Properties of the Quaternary Heusler CoZrFeP

Many studies nowadays are available to predict the half-metallic behaviour of Heusler’s quaternary compounds. Using the first principle study of the quaternary Heusler CoZrFeP, we examined its structural, electronic and magnetic properties with the full-potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA) and the generalized modified potential plus Becke-Johnson approximation (GGA-mBJ). Our quaternary Heusler CoZrFeP compound has shown a half-metallic ferromagnetism character with a small band gap in the minority spin which makes it an excellent candidate for the development of new devices in spintronic and magnetoelectronic. In order to know whether our Heusler quaternary CoZrFeP compound can be experimentally synthesized, we studied its mechanical stability by calculating its formation energy, cohesion energy and elastic constants.

Exploration of uranium double perovskites Ba2MUO6 (M = Co, Ni) for magnetism, spintronic and thermoelectric applications

Ba2MUO6 (M = Co, Ni) alloys are investigated to understand their electronic structure, magnetic character together with thermoelectric behavior using ab-initio formulism. The variations in physical properties by changing M-site atom are analyzed. The crystal structure of Ba2MUO6 (M = Co, Ni) alloys is found to be face-centered cubic (Fm-3m) with lattice constant of 0.845 nm for Ba2CoUO6 and 0.841 nm for Ba2NiUO6. The band structure and density of states convey half-metallic ferromagnetic character of Ba2CoUO6, while Ba2NiUO6 exhibit ferromagnetic semiconducting nature. The electron filling in the d-orbitals of Co and Ni determines the overall electronic and magnetic character of alloys. The obtained structural parameters and magnetic moment are consistent with experimental results. The variation in various thermoelectric parameters with temperature is also examined. The highest value of power factor obtained for Ba2NiUO6 and Ba2CoUO6 is 54.92 μW cm−1 K−2 and 9.25 μW cm−1 K−2, respectively. The semiconducting nature in both spin orientations favors Ba2NiUO6 for thermoelectric applications. The computed elastic constants along with other elastic parameters suggest that these alloys are mechanically stable and possess ductile character.

First-Principle Predictions of Electronic Properties and Half-Metallic Ferromagnetism in Vanadium-Doped Rock-Salt CaS

The objective of this study is to theoretically investigate the electronic, structural and magnetic properties of calcium sulfide (CaS) doped with transition metal vanadium (V) at various concentrations of this element in the rock-salt phase. All properties of Ca1−xVxS compounds are achieved using the full potential linearized augmented plane wave (FP-LAPW) method with a density functional theory (DFT) implemented in WIEN2 K code. The results obtained show that the Ca0.75V0.25S and the Ca0.50V0.50S compounds are of half-metallic ferromagnetic (HMF) character at a 100% spin polarization, which makes them potential candidates for spin injection applications in spintronic devices, while the Ca0.25V0.75S compound depicted a nearly half-metallic character. In all compounds, the data of the magnetic moment demonstrated that the vanadium impurity atom (3 μB) is the most important source by comparison with the Ca and S, which have minor contributions. In addition, the half-metallic gap (GHM) is an important parameter to consider for potential applications in spintronic devices, which are 0.916 eV and 0.315 eV, respectively, for Ca0.75V0.25S and Ca0.50V0.50S compounds, while for x = 0.75, it is destroyed due to the broadening of 3d states of vanadium impurity in the gap. However, an experimental confirmation is needed to confirm our predictions.

Half-Metallic Ferromagnetism Character in Cr-Doped CaS Diluted Magnetic Insulator and Semiconductor: an Ab Initio Study

The overall aim of this study is to investigate theoretically the structural, electronic, and magnetic properties of calcium sulfide (CaS) doped with chromium (Cr) impurity, in order to conduct a new search dilute magnetic semiconductors (DMS) suitable for different applications in electronics and spintronics. For measuring, the physical property of this compound is implemented using the first principles approach employed in WIEN2K code. The structural characteristics are optimized using the Generalized Gradient Approximation established by Perdew-Burk-Ernzerhof (PBE-GGA). We calculate and minimize the total energy of the three ternary compounds (Ca0.75Cr0.25S, Ca0.50Cr0.50S, and Ca0.25Cr0.75S) in the paramagnetic (PM), ferromagnetic (FM), and antiferromagnetic (AFM) phase. We find all compounds stable in (FM) structure, whereas the modified Becke and Johnson local density approximation (mBJ-LDA) functional has been employed to evaluate the electronic and magnetic properties. Based on our findings, indicate that this system revealed a half-metallic ferromagnetic behavior with half-metallic gap (HM) and 100% spin-polarized at the fermi level for all chromium (Cr) concentrations. This advantageous set of properties is due to the half-metallic behavior, where the majority spin and minority spin exhibit metallic and semiconducting behaviors respectively. The chromium atom is the most important source of the total magnetic moment in these compounds (4 μβ) by comparison with magnetic moments produced by Ca and S atoms, which have minor contribution. Finally, our prediction results require an experimental confirmation in the future.

Half Metallic Ferromagnetic Character in ZnXP2 (X = Ge, Si) Chalcopyrites Doped with Mn

The electronic and the magnetic properties of ZnXP2 (X = Ge, Si) were studied using the Korring-Kohn-Rostoker (KKR) method combined with the coherent potential approximation (CPA). The total and partial density of state (DOS) are computed for different Mn concentrations. The total magnetic moment, FM and DLM energies, and their variation as well as Curie temperature are also given. It is shown that the substitution of X cations (X = Ge, Si) by Mn atoms in ZnXP2 chalcopyrites leads to half metallic ferromagnetic character with double exchange mechanism. Thus, the critical temperature can be controlled by varying the concentration of manganese impurity.

Theoretical investigation of electronic performance, half-metallicity, and magnetic properties of Cr-substituted BaTe

We have investigated the structural, electronic, and ferromagnetic properties of chromium (Cr)-doped rocksalt BaTe ( $$\hbox {Ba}_{1-x}\hbox {Cr}_{x}\hbox {Te}$$ ) compounds with compositions $$x = 0.25$$ , 0.5, and 0.75, based on density functional theory with generalized gradient approximation of Wu–Cohen (GGA-WC) and Tran–Blaha-modified Becke–Johnson (TB-mBJ) potential using the WIEN2k package. We found that the electronic structure showed half-metallic ferromagnetic character with spin polarization of 100 % around the Fermi level. In addition, the minority-spin bands depicted a half-metallic ferromagnetic (HMF) gap and half-metallic (HM) gap. The improved HMF and HM gaps found with the TB-mBJ potential are higher than with the GGA-WC approximation. These large HM gaps make $$\hbox {Ba}_{1-x} \hbox {Cr}_{x}\hbox {Te}$$ compounds promising candidates for use in spintronics applications.

Increase of Curie temperature with La doping in the double perovskite Sr2-LayFeMoO6 within an electronic correlation approach

The double perovskite compound Sr2FeMoO6 has a half-metallic ferromagnetic character and ahigh Curie temperature (420 K). Fe-Mo usually present some degree of disorder in either Fe orMo ions, it is therefore fundamental to understand the role of electronic and structural parameterscontrolling the half-metallic character together with a Curie temperature as high as possible. We replaceddivalent Sr2+ by trivalent La3+ ions in Sr2FeMoO6 system to observe the Curie temperaturebehavior. We present an electronic approach using the Green's functions and the renormalizationperturbation expansion method, with localized Fe-spins and conduction Mo-electrons interactingwith the local spins via a double-exchange-type mechanism. We also include the electronic correlationsamong the conduction electrons within a mean-eld approximation. Our results showthe density of states and the Curie temperature behavior when La concentration increases for theSr2y-yLayFeMoO6 system

Theoretical investigation of the electronic and magnetic properties of Zn (Fe, Co) Se: Ab initio calculations and Monte Carlo simulations

On the basis of spin density functional calculation, the electronic and magnetic properties of ZnSe doped with double impurities Zn1-2xFexCoxSe (x = 0.05) are studied using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method within the local density approximation (LDA). The half-metallic ferromagnetic nature of (Fe, Co) doped ZnSe is investigated. Therefore the electronic structure and magnetic properties of Zn1-2xFexCoxSe exhibit a half-metallic ferromagnetic character; the stability of ferromagnetic (FM) compared to the disorder local moment (DLM) has been discussed. Our calculation is supported by Monte Carlo simulations (MCS) based on the heat bath algorithm. We have examined the effects of system size L on magnetization, specific heat and magnetic susceptibility. The spin density functional calculation results are in good agreement with the literature, especially for 5% of (Co, Fe) each, which gives the most interesting results.