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In this paper, we employed Density Functional Theory (DFT) to study structural and mechanical stability, electric, magnetic and electronic properties of cubic Co-based new quaternary half-Heusler alloys CoZrCrZ (Z = Al, Ga, In) using WIEN2k. Volume optimisation suggests that these alloys are stable in the Y1 structure and show ferromagnetic behavioTAur. Generalised Gradient approximation calculations confirm the half-metallic nature of the reported alloys, which show metallic nature, and semiconducting band gaps exist in spin-up and spin-down channels, respectively. From the calculated cubic elastic constants, the reported Heusler alloys shows ductile nature. The calculated spin-magnetic moments of CoZrCrZ (Z = Al, Ga, In) are consistent with the Slater-Pauling rule. The very fine narrow band gap in the spin-down channel enhances the thermoelectric properties. The reported ferromagnetic half-metals with good thermoelectric parameters suggests that these alloys have possible applications in spin-based electronics and green energy technology. [ABSTRACT FROM AUTHOR]

Near stoichiometric Co2FeSn Heusler alloy films with a highly ordered L21 structure and mean grain size of 23 ± 1 nm have been prepared on a polycrystalline copper substrate for the first time by electrodeposition route. Deposition potential −4.0 V yielded the stoichiometric alloy composition in the potentiostatic mode. The highly disordered as-deposited alloy film crystallized into the ordered stable Heusler alloy structure upon heat treatment under vacuum. The heat-treated film exhibited the highest magnetic moment (5.18 ± 0.04 μB/f.u. at 5 K) and Curie temperature (1123 K) ever achieved in this alloy in any form. The very high value of Keff (∼106 erg c.c.−1) obtained for this alloy makes this alloy promising for high-density magnetic recording application. Ab initio studies using GGA + U approach provide information on the minority gap near the Fermi level and its tunability as a function of the electron correlation factor represented by the Hubbard parameter U. [ABSTRACT FROM AUTHOR]

• The bulk FeMnSb exhibits half-metallic ferrimagnetism with 100% spin-polarization. • The MnSb-terminated surface maintains half-metallicity, essential for spintronic applications. • The Fe-Ga interface achieves 97.316% spin-polarized current, indicating strong spin-polarization. • Absorption coefficient peaks shift from the UV region in the bulk alloy to the visible region at the (001) surfaces. • At FeMnSb/GaAs and FeMnSb/GaP interfaces, the highest absorption peaks return to the UV region. We systematically investigated the electronic, magnetic, and optical properties of the FeMnSb half-Heusler alloy, its (001) surface, and its interfaces with GaAs and GaP semiconductors by using first-principles calculations based on density functional theory. The bulk FeMnSb reveals its half-metallic ferrimagnetism with 100% spin-polarization. Extending this study to the (001) surface, we uncover distinct electronic and magnetic behaviors for Fe- and MnSb-terminated surfaces, the MnSb-terminated surface preserving the half-metallicity observed in the bulk material. Our evaluation of the interfaces exhibits positive work of separation, indicating that these interfaces are energetically favorable. The density of states analysis reveals that all interfaces exhibit a metallic nature. High spin-polarization values, particularly 97.316% for the Fe-Ga interface, suggest a substantial degree of spin-polarized current. Notably, the absorption coefficient peaks shift from the ultraviolet (UV) region in the bulk alloy to the visible region at the (001) surfaces. However, at the FeMnSb/GaAs and FeMnSb/GaP interfaces, the highest absorption peaks revert to the UV region, highlighting strong interfacial coupling effects. These results suggest the tunability of FeMnSb optical properties via surface termination and interface engineering, making it a promising candidate for spintronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this paper, nanostructured Co2FeGa Heusler alloy films with L21, B2 and A2-type cubic structures were synthesized using a lowcost electrodeposition method for the first time. The crystal structure of the deposited Co2FeGa is dependent on pH of electrolyte. Magnetic measurements show that the saturation magnetization and coercivity of the samples have a positive correlation with the pH of electrolyte. The relationships of the microstructure and magnetic properties of the samples were discussed. The electrodeposited Co2FeGa films with a high magnetization and low coercivity in our work will be of particular interest in industrial and technology applications. [ABSTRACT FROM AUTHOR]

In our study, the Cr2VAs full-Heusler alloy was investigated using the ab initio GGA+U technique. The outcomes show that in a ferromagnetic state, structures are stable. Electronic structure study reveals semi-metallic behavior with a small indirect gap of 0.31 eV along (-X) in the mBj scheme and a narrow direct gap in the (-) direction under GGA+U. Mechanical stability is predicted by elastic studies for a Debye temperature of 276.534 K. In spintronics, this ternary alloy shows potential. [Display omitted] • Determine the structural, magnetic, electronic and mechanical characteristics of Cr 2 VAs. • Cr 2 VAs has a semimetal nature with direct gap along Γ- Γ direction using GGA. • The computed total magnetic moments accord well with the Paulig-Slater criteria. • mBj scheme exhibited a large rise in magnetic moments. This study employs the full-potential linearized plane wave method (FP-LAPW) within the generalized gradient scheme GGA, incorporating the Hubbard correlation parameter U. The application of this approach enables a comprehensive exploration of the structural parameters, electronic structure, magnetic properties, and elastic properties of the Cr2VAs full-Heusler alloy through advanced computer simulations. The analysis of structural properties unequivocally reveals the stability of the Cr2VAs system in ferromagnetic states. Employing GGA, our examination of the electronic structure indicates semi-metallic properties, showcasing a direct gap along the (Γ-Γ) direction. In contrast, within the GGA + U approach, Cr2VAs adopts a nearly half-metallic character in the same direction. Furthermore, under the mBj scheme, the compound exhibits a distinctive half-metallic nature with an indirect band gap of 0.31 eV along the (Γ-X) direction. The results from elastic studies lead to the conclusive finding that the investigated material demonstrates mechanical stability, supported by a Debye temperature of 276.534 K. The computed outcomes underscore the promising potential of this ternary alloy in the field of Spintronics. [ABSTRACT FROM AUTHOR]

Abstract We investigated the thermoelectric transport mechanism of ZrNiSn and ZrNiPb Half-Heuslers within the Boltzmann transport theory, under constant relaxation time approximation. The prediction of band structure behavior along the high symmetry Brillouin zone and density of states are used to establish relations among various transport coefficients like Seebeck coefficient, electrical conductivity, thermal conductivity and power factor which have been found to be in good agreement with the experimental results. The Seebeck coefficient variation show the n -type behavior of heat carriers. The electrical and thermal conductivity show a semiconducting nature of bands along the Fermi level. The lattice part of thermal conductivity show an exponential decreasing trend along the high temperatures. Power factor variation and figure of merit show the heavier element doping of ZrNiSn results in descent increase in efficiency triggering its applicability. The overall measurements show that semi classical Boltzmann transport theory has well behaved potential in predicting the transport properties of the compounds. [ABSTRACT FROM AUTHOR]

• The CsVF 2 , CsVCl 2 , CsVI 2 and CsCrI 2 alloys are all HM ferromagnets while remaining alloys exhibits MSC behavior. • Their total magnetic moments are 4 and 5µ B /f.u. for CsVZ 2 and CsCrZ 2 , respectively. • Their Curie temperatures are higher than room temperature and thus usable in spintronics. As for spintronic applications, all information is encoded in the spin degree of freedom, so the key issues are the high spin-polarization, large half-metallic (HM) bandgap, large magnetic moment and higher Curie temperature than room temperature. In this paper, we studied halogen based CsYZ 2 (Y = V or Cr; Z = F, Cl, Br or I) full-Heusler alloys. Our study reveals that CsVF 2 , CsVCl 2 , CsVI 2 and CsCrI 2 alloys are all HM ferromagnets while remaining alloys exhibits magnetic semiconductor behavior. The electronic structures indicate that these alloys open very large bandgaps in the spin-down channel. Following the Slater-Pauling rule M t = Z t -16 , these alloys exhibit very large total magnetic moments M t of 4.00 μ B f.u. when Y = V and 5.00 μ B f.u. when Y = Cr. The high Curie temperatures indicate these alloys are appropriate for spintronic applications at room temperature. Furthermore, the absorption coefficient α(ω) of the CsVF 2 alloy is better from other alloys in the visible region. The maximum ZT = 0.7 is obtained for CsCrBr 2 and is an ideal candidate for thermoelectric (TE) applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heusler alloys are promising materials for several technological applications, including thermoelectric devices. • The type of atom located in the 4c/8c position is crucial for the formation of the covalent-polar chemical bonds in the HH-1 and FH-1 structures. • CoTaSn structure presents a semiconductor character, where the Co atom occupies the Wyckoff 4c position. • Co 2 TaSn structure presents a half-metal character, where the Co atom occupies the Wyckoff 4c and 8c positions. • CoTaSn p-type system presents to be more promising to TE applications. Heusler alloys have shown to be promising materials for thermoelectric applications. This work presents a theoretical study of Heusler alloys within the GGA-PBE and hybrid (HSE06) approaches. The cubic (C1b) CoTaSn half-heusler compound exhibits semiconductor characteristics and a bandgap of 1.18 eV, when Co occupies the Wyckoff 4c site. On the other hand, the cubic (L21) Co 2 TaSn full-heusler is a half-metal with a bandgap of 1.36 eV in the spin up channel, when Co in the Wyckoff 4c/8c sites. For both systems, the total magnetic moment agrees with the prediction given by Slater-Pauling rule. The analysis from the Bader charge and ELF functions indicates a formation of covalent-polar bonds in the studied alloys. Also, effective masses were obtained, highlighting this as an important feature for high performance thermoelectrics. From Wannier functions, the thermoelectric parameters were calculated for the CoTaSn alloy and the results compared with the experimental data available in literature. [ABSTRACT FROM AUTHOR]

• There is no significant atomic occupation preference of Cd 2 MnY (Y = Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt). • For Cd 2 FeMn, Cd 2 NiMn and Cd 2 PdMn, their L2 1 -type is more stable than XA-type, and others are the opposite, which indicates that the compounds do not comply with the traditional SPR. • Both XA type and L21 type structures show excellent shape memory metal properties. Based on the first principle calculations, the atomic site occupations, electronic structures, magnetic properties and martensitic transformations of all-d-metal heusler alloys Cd 2 MnY (Y = Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt) were studied. For their cubic phase, the cubic XA-type atomic occupation of Cd 2 MnRu, Cd 2 MnOs, Cd 2 MnCo, Cd 2 MnRh, Cd 2 MnIr and Cd 2 MnPt are more stable, and the L2 1 -type atomic occupation of Cd 2 MnFe, Cd 2 MnNi and Cd 2 MnPd are more stable, which show that there is without atomic site preferences in these all-d-metal heusler alloys. The total energy of XA-type and L2 1 -type of tetragonal phase of all alloys is lower than that of cubic phase, so XA-type and L2 1 -type of all alloys Cd 2 MnY are likely to undergo martensitic transformation. [ABSTRACT FROM AUTHOR]

Heusler type alloys Ni50Mn25+xGa25-x (x = 2, 3, 4, and 5) based on near stoichiometric Ni2MnGa compositions were directionally solidified using modified Bridgman method. The alloys thus prepared were characterised for their chemical composition, crystal structure, microstructure, phase transformation, magnetic and magneto-mechanical properties. The directionally solidified Ni50Mn30Ga20 alloy rod exhibited maximum magnetocrystalline value of 95 kJm-3 and lowest detwinning stresses for martensite phase of about 5 MPa. The reversible room temperature magnetic field induced strain of 0.2 per cent under external magnetic field of 0.6 T and 0.05 kN bias load was obtained for the directionally solidified Ni50Mn30Ga20 alloy. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the magnetic noise dependence on the sense current, I sense , and the hard bias field, H B , of the current perpendicular to the plane giant magnetoresistance read heads. The macrospin modeling was performed in the simulations. The magnetic noise was examined by using power spectral density analysis. The results showed that the magnetic noise was increased with increasing I sense due to an enhancement of STT effect, especially a rapid increase of the noise was found when I sense exceeds a critical value. An asymmetry of I sense indicated that a negative current produces lower noise than a positive current since a ferromagnetic exchange coupling was existed in the model. In addition, the noise could be reduced by increasing H B which further results in an increase of the ferromagnetic resonance frequency. Hence, an optimization of I sense and H B strongly influences the magnetic noise and becomes an important factor for acheiving the high performance magnetic read head for higher recording densities. [ABSTRACT FROM AUTHOR]

Co2FeSn Heusler alloy nanowires with the diameters of 30 nm and 60 nm were firstly prepared by direct current electrodeposition. Magnetic measurements revealed the excellent soft ferromagnetism of Co2FeSn nanowires. The easy magnetization axis is perpendicular to the long axis of nanowires and the magnetic reversal of Co2FeSn nanowires occurs via coherent rotation model. In addition, the influence of the wire diameter on the magnetic properties of Co2FeSn nanowires was discussed. Co2FeSn Heusler alloy nanowires synthesized in this work shows tunable magnetic properties and are of potential interest for magnetic device and spintronic applications. [ABSTRACT FROM AUTHOR]

The present manuscript reports structural stability, half-metallic behavior, thermophysical and thermoelectric properties of Co 2 MoAl and Co 2 TcAl full Heusler compounds using first-principle calculations. The full-potential linearized augmented plane wave method within the framework of density functional theory is implemented and WIEN2k code is incorporated in the stable Fm -3 m phase to attain the desired results. The L2 1 phase is found as the most stable phase for both compounds. The optimized equilibrium lattice parameters in the stable phase are 5.89 Å, 5.86 Å for Co 2 MoAl and Co 2 TcAl respectively. The electronic band structure study proves that both compounds Co 2 MoAl and Co 2 TcAl have indirect band gaps of 0.74 eV and 0.85 eV respectively in majority spin alignment. The half-metallic character of the present set of compounds is explained by the spin-resolved density of states. The Fermi level at the Brillouin zone point decides the metallic as well as semiconducting behaviour. [Display omitted] • Spintronics applicability of Co 2 YAl (Y = Mo, Tc) Heusler alloys is computationally studied. • Effect of pressure on the magnetic moment is studied which reports that it considerably reduces the magnetic moment. • Cohesive and formation energy values confirm the possibilities of experimental synthesis. • Half metallic and thermodynamic performance has been predicted successfully. The present manuscript reports structural stability, half-metallic behavior, thermophysical and thermoelectric properties of Co 2 MoAl and Co 2 TcAl full Heusler compounds using first-principle calculations. The full-potential linearized augmented plane wave method within the framework of density functional theory is implemented and WIEN2k code is incorporated in the stable Fm -3 m phase to attain the desired results. The L2 1 phase is found as the most stable phase for both compounds. The optimized equilibrium lattice parameters in the stable phase are 5.89 Å, 5.86 Å for Co 2 MoAl and Co 2 TcAl respectively. The electronic band structure study proves that both compounds Co 2 MoAl and Co 2 TcAl have indirect band gaps of 0.74 eV and 0.85 eV respectively in majority spin alignment. The half-metallic performance of the present set of compounds is explained by the spin-resolved density of states. The Fermi level at the Brillouin zone point approves the metallic as well as semiconducting behavior. To elucidate the thermodynamical stability of these materials against pressure and temperature by implementing the quasi-harmonic approximation of various parameters like Debye temperature, Gruneisen parameters and specific heat are studied successfully. To know the thermoelectric response, Seebeck coefficient and electrical conductivity are computed using the BoltzTrap code. The thermodynamic profile delivers that the present set of compounds possesses no anomalies with respect to the phase transition or instabilities. The computational study insights that the compounds can be synthesized experimentally and find a route towards spintronic and thermoelectric applicability. [ABSTRACT FROM AUTHOR]

First principles band structure calculations coupled with the Boltzmann transport theory are used to study the thermoelectric properties in TiCoSb under pressure. The density of states and band structure were studied in detail. The thermoelectric power, electrical conductivity and electronic thermal conductivity were analysed using the Boltzmann transport equation with the assumption of the constant relaxation time approximation and the rigid band model. The enhancement of the thermoelectric properties of TiCoSb by adjusting pressure is predicted. [ABSTRACT FROM AUTHOR]

Synthesis of Co2FeSn Heusler alloy using a simple and low-cost electrodeposition method is reported for the first time. The effect of deposition current density on crystal structure, chemical composition, morphology and magnetic properties of the samples was studied. The electrodeposited Co2FeSn alloy showed a nanocrystalline structure. Magnetic measurement reveals that the obtained Co2FeSn are soft magnetic at room temperature with the coercivity of 32 Oe. The saturation magnetic moment of the electrodeposited Co2FeSn alloy at 5 K is estimated to be 4.5 μB/f.u. The relationship between the microstructure and magnetic properties of the samples was discussed. [ABSTRACT FROM AUTHOR]

Abstract: The effect of titanium (Ti) substitution for hafnium (Hf) on thermoelectric properties of (Hf, Zr)-based n-type half-Heuslers: Hf0.75−x Ti x Zr0.25NiSn0.99Sb0.01, has been studied. The samples are made by arc melting followed by ball milling and hot pressing via the nanostructuring approach. A peak thermoelectric figure-of-merit (ZT) of ∼1.0 is achieved at 500°C in samples with a composition of Hf0.5Zr0.25Ti0.25NiSn0.99Sb0.01 due to a slight increase in carrier concentration and also a lower thermal conductivity caused by Ti. The ZT values below 500°C of hot pressed Hf0.5Zr0.25Ti0.25NiSn0.99Sb0.01 samples are significantly higher than those of the same way prepared Hf0.75Zr0.25NiSn0.99Sb0.01 samples at each temperature, which are very much desired for mid-range temperature applications such as waste heat recovery in automobiles. [Copyright &y& Elsevier]

Abstract: In this work the coupled magnetostructural and premartensitic phase transitions in Heusler Ni–Mn–Ga alloy have been modeled by Monte Carlo method using Ising and Blume–Emery–Griffiths models. The phase diagrams in coordinates (Temperature–Magnetoelastic constant) were obtained. For the first time it is shown that the magnetoelastic interaction account in austenitic and martensitic phases allows to describe the coupled magnetostructural phase transition in Ni-Mn-Ga alloys. The area of the premartensitic phase transition in the temperature–magnetoelastic constant diagram has been found. [ABSTRACT FROM AUTHOR]

[Display omitted] • Equivalent quaternary Heusler alloys CoCrScSb, CoCrTiSb, CoCrVSb are proposed. • CoCrScSb and CoCrVSb exhibit half-metallic character in the cubic ground state. • CoCrScSb is more inclined to tetragonal deformation than cubic phase. • The mechanical stability of CoCrScSb and CoCrVSb has been verified. • The anisotropy of CoCrScSb and CoCrVSb is very obvious. The structural configuration and phase stability of quaternary Heusler alloys CoCrScSb, CoCrTiSb and CoCrVSb have been systematically investigated. The results show that type-Ⅰ configuration in the cubic ferromagnetic phase has the lowest total energy, and the CoCrScSb and CoCrVSb exhibit half-metallic behavior under cubic ground state. The hull distance justify that the alloys CoCrScSb and CoCrVSb can be considered to be thermodynamically stable and suitable for experimental synthesis. The tetragonal phase transformation was investigated using the total energy change method. It was found that the deformation of CoCrScSb contributes to the energy reduction, with c/a = 1.25 being at the lowest value of energy. Under tetragonal phase the CoCrScSb exhibits metallic behavior. However, the deformation of the alloys CoCrTiSb and CoCrVSb did not reduce the total energy compared to the cubic phase. Elastic studies indicate that CoCrScSb, CoCrTiSb and CoCrVSb have stable mechanical properties, which provides the possibility for their engineering application. [ABSTRACT FROM AUTHOR]

The article discusses the materials scientists at Duke University in the U.S. which have predicted and created two new magnetic materials through computational models. It states that the researchers used Heusler alloys which are group of compounds that contain several magnets and mapped all the possible chemical combinations excluding the toxic, explosive and radioactive elements.