Linear Augmented Plane Wave Method Research Articles

Optoelectronic and thermodynamic properties of the Yttrium filled skutterudite YFe4P12

In this work, we sought to understand the structural, electronic, optical, and thermodynamic properties of the compound YFe4P12 using the full-potential and linear augmented plane-wave method (FP-LAPW) based on density functional theory (DFT), our calculation of the lattice parameter of this compound YFe4P12 is reasonably in good agreement with the experimental results. Calculations carried out on the electronic band structure showed that the YFe4P12 compound is classified as a direct-gap Half- half-metallic in the minority spins. Moreover, optical properties, such as the optical absorption coefficient, real and imaginary parts of the dielectric function, optical conductivity, refractive index, and optical reflectivity have been studied. The effects of pressure and temperature on the lattice parameter, heat capacities, coefficients of thermal expansion, entropy, and Debye temperature were explored using the quasi-harmonic Debye model.

Structural and Photoluminescence Properties of Ca2+-Substituted Self-Activated Photoluminescence Material of Na2TiSiO5

The effects of Ca2+ substitution on the structural and optical properties of Na2TiSiO5 were studied. It was expected that the Ca2+ ions would replace Na+ ions and change the coordination of Ti4+-O2- as a luminescence center. Na2(1‑x)CaxTiSiO5 (x = 0.00, 0.50, 1.00) samples were synthesized using the solid-state method, and their structural properties, the local Ti4+-O2- coordination, the absorption spectra, and the photoluminescence properties were studied. The electronic structure of Na2(1-x)CaxTiSiO5 with x = 0.00 and 1.00 was also calculated using the Full Potential Linear Augmented Plane Wave (FP-LAPW) method to explain some of the observed properties. The Ca2+ substitution resulted in a phase transformation from an orthorhombic to a monoclinic structure. The number of TiO6 octahedra increased with the increase of Ca2+ and correlated with the decrease of PL emission intensity of the Na2(1‑x)CaxTiSiO5 samples. The Ti-3d bands in the CaTiSiO5 were more dispersive than in the Na2TiSiO5 and were responsible for the PL emission intensity reduction.

Investigating the structural, electronic, and magnetic properties of Cd1-xVxTe: Insights from First-Principles calculations

In our study, we aim to investigate the structural, electronic, and magnetic properties of CdVTe, a diluted magnetic semiconductor with a Cadmium telluride (CdTe) structure. To achieve this, we employ the full potential linear augmented plane wave method implemented in the CASTEP code, which allows us to accurately simulate the behavior of the system. To describe the electronic exchange and correlation effects, we adopt the generalized gradient approximation (GGA) within the density functional theory (DFT) framework. This choice of methodology ensures reliable and accurate calculations of the electronic and magnetic properties of Cd1-xVxTe. Our results reveal that the substitution of Vanadium (V) into the Cadmium (Cd) site of the CdTe lattice does not alter the zinc blende crystal structure, demonstrating the stability and structural integrity of the system. Furthermore, our calculations demonstrate that the introduction of Vanadium impurities leads to spin polarization within the material, resulting in the emergence of a magnetic moment. Notably, we find that a Vanadium concentration of approximately x≈0.12 exhibits the strongest magnetic properties, characterized by a significant magnetic moment. These findings provide valuable insights into the behavior and potential applications of CdVTe as a diluted magnetic semiconductor, shedding light on the interplay between structural, electronic, and magnetic properties in this material.

Optoelectronic and thermoelectric properties of novel double halide perovskites Na2AgAsX6 (X = Cl, Br) for efficient green solar cells

Inorganic lead-free double halide perovskites have emerged as promising materials in photovoltaic and renewable energy applications. This study investigates the optoelectronic and thermoelectric properties of novel inorganic lead-free double halide perovskite Na2AgAsX6 (X = Cl, Br) materials using accurate PBEsol and nKTB-mBJ schemes within the powerful full potential linear augmented plane wave (FP-LAPW) method. Structural ground state parameters were optimized, and the structural stability of these materials was assessed by evaluating their formation energy, phonon frequencies, and tolerance factor. Analysis of the electronic structure reveals that Na2AgAsX6 exhibit an indirect gap character, with energy values of 2.0 (for Cl) and 1.29 eV (for Br). Additionally, we computed various optical properties including dielectric functions (ε1, ε2), absorption coefficient (α), refractive index (n), extinction coefficient (k), and reflectivity (R), demonstrating a broad absorption spectrum spanning from visible to ultraviolet wavelengths. Furthermore, the investigation extends to determine the electronic transport properties—Seebeck coefficient (S), electrical conductivity (σ/τ), power factor (PF), thermal conductivity (κe/τ), and figure of merit (ZT) for Na2AgAsX6 (X = Cl, Br), using BoltzTraP code. These findings underscore the substantial potential of Na2AgAsX6 (X = Cl, Br) halide perovskites as efficient light absorption layers in the development of high-performance perovskite solar cells (PCSs) and also hold promise for future eco-friendly thermoelectric generator applications.

Structural Analysis, Characterization, and First-Principles Calculations of Bismuth Tellurium Oxides, Bi6Te2O15

A single crystal of Bi6Te2O15 was obtained from the melt of the solid-state reaction of Bi2O3 and TeO3. Bi6Te2O15 crystallizes in the Pnma space group (No. 62) and exhibits a three-dimensional network structure with a =10.5831(12) Å, b = 22.694(3) Å, c = 5.3843(6) Å, α = β = γ = 90°, V = 1293.2(3) Å3, and Z = 4. The structure was determined using single-crystal X-ray diffraction. An asymmetric unit in the unit cell, Bi3Te1O7.5, uniquely composed of four Bi3+ sites, one Te6+ site, and nine O2− sites, was solved and refined. As a bulk phase, Bi6Te2O15 was also synthesized and characterized using powder X-ray diffraction (XRD), infrared (FT-IR) spectrometry, and the thermogravimetric analysis (TGA) method. Through bond valence sum (BVS) calculations from the single crystal structure, Bi and Te cations have +3 and +6 oxidation numbers, respectively. Each Bi3+ cation forms a square pyramidal structure with five O2− anions, and a single Te6+ cation forms a six-coordinated octahedral structure with O2− anions. Since the lone-pair electron (Lp) of the square pyramidal structure, [BiO5]7−, where the Bi+ cation occupies the center of the square base plane, exists in the opposite direction of the square plane, the asymmetric environments of all four Bi3+ cations were analyzed and explored by determining the local dipole moments. In addition, to determine the extent of bond strain and distortion in the unit cell, which is attributed to the asymmetric environments of the Bi3+ and Te6+ cations in Bi6Te2O15, bond strain index (BSI) and global instability index (GII) were also calculated. We also investigated the structural, electronic, and optical properties of the structure of Bi6Te2O15 using the full potential linear augmented plane wave (FP-LAPW) method and the density functional theory (DFT) with WIEN2k code. In order to study the ground state properties of Bi6Te2O15, the theoretical total energies were calculated as a function of reduced volumes and then fitted with the Birch–Murnaghan equation of state (EOS). The band gap energy within the modified Becke–Johnson potential with Tran–Blaha parameterization (TB-mBJ) revealed a value of 3.36 eV, which was higher than the experimental value of 3.29 eV. To explore the optical properties of Bi6Te2O15, the real and imaginary parts of the dielectric function, refraction index, optical absorption coefficient, reflectivity, the real part of the optical conductivity extinction function, and the energy loss function were also calculated.

Exploring properties of organometallic double perovskite (CH3NH3)2AgInCl6: A novel material for energy conversion devices

Distinct types of materials are being explored for usage in thermoelectric (TE) and photovoltaic (PV) systems in order to alleviate the energy problem. In order to create nontoxic, more stable, and best-performance energy convergence devices, the state-of-the-art hybrid halide double perovskites (HHDPs) compound has been identified as a potential TE material and potential replacement for hazardous lead. We have proposed a new HHDP material (CH3NH[Formula: see text]AgInCl6 and performed its theoretical investigation via the full potential linear augmented plane wave (FP-LAPW) method. The computational results show that the studied compound exhibits a direct bandgap of 3.708[Formula: see text]eV and has exceptional PV characteristics in the ultraviolet (UV) region. The obtained thermodynamic (TD) characteristics confirm that the titled compound is thermally stable at various temperatures and pressures. At 300 K, the examined HHDP material has the highest ZT (=2.23) in the p-region. Materials with higher ZTe values are substantially more important for generating electrical energy through waste heat. The ZTe result validates the use of these materials in TE devices at ambient temperature. The parameters of this compound have been computed for the first time. This study identifies (CH3NH[Formula: see text]AgInCl6 as a novel HHDP compound. Through an in-depth exploration of its properties, this study offers valuable insight for further research with potential applications in clean energy systems.

Variation of cation-ligands XAl2Ge2 (X = Pr, Nd, Gd, Tb) compounds by employing density functional theory

The present report aims to examine detailed Cationic ligands replacement for XAl2Ge2 (X = Pr, Nd, Gd, Tb) compounds by employing the density functional theory (DFT) within full-potential linear augmented plane wave (FP LAPW) method. For the structural determination, the generalized gradient (PBE-GGA) approximation has been used to get theoretical reliable and analogous results with the available experimental data. We have further established that the ferromagnetic phase is more stable and suitable for calculation of the magnetic properties. The two approximations namely (PBE-GGA and GGA+U) are used for the investigation of band structures. The band structures along with density of state (DOS) plots approve the metallic character of XAl2Ge2. There exists a strong hybridization between (Pr, Nd, Gd, Tb) f and (Al, Ge) s, p states. Also, the examination of magnetic properties confirms a strong ferromagnetism in XAl2Ge2 compounds.

Electronic structure, theoretical power conversion efficiency, and thermoelectric properties of bismuth-based alkaline earth antiperovskites.

This research paper investigates the properties and potential applications of antiperovskite materials. Antiperovskites are a class of materials with a unique crystal structure, where the central atom is surrounded by a cage of anions. We review recent research on antiperovskite-based materials for energy storage, photovoltaics, catalysis, and sensors. We discovered that these materials display direct band gap semiconductors, strong absorption in the visible (VIS), ultra-violet (UV), and near infrared regions (NIR) based on their fundamental features, which is the most admirable quality that may be found in many optoelectronic devices. Both mechanical and thermodynamic stability have been confirmed for these materials. We discovered that these materials exhibit high figures of merit through the calculation of transport properties, which makes them a promising candidate for thermoelectric devices. It is anticipated that the proposed material BiPMg3, which has a theoretical efficiency of 11.5%, will make a suitable photovoltaic absorber. This paper highlights the potential of these materials for future technological advancements. Herein, we have used most authentic techniques to compute fundamental physical properties of these antiperovskites. Full-potential linear augmented plane wave (FP-LAPW) method has been used to investigate electronic, magnetic, optical properties, and make antiperovskites attractive for a variety of applications. In light of its implementation, we have checked the theoretical power conversion efficiency by first principles spectroscopic screening methodology, and inspect the fundamental physical parameters of antiperovskites, focusing on their potential as functional materials for energy and information technologies.

Structural and electronic properties of Ba[formula omitted]TiMnO[formula omitted] from first principles

In this study, we present ab-initio calculations of the structural, spin arrangement properties, and electronic properties of the Ba2TiMnO6 double perovskite. Our calculations employ the Full-Potential Linear Augmented Plane-Wave method (FP-LAPW) method and both Local Spin Density (LSDA) and Generalized Gradient (GGA) approximations. We additionally take into account the relativistic effects of spin–orbit coupling and the Hubbard term corrections U and J. According to our findings, the most stable magnetic structure is antiferromagnetic, with collinear Mn spins aligned along the [001] direction and an ordered moment μord of roughly 2.56 μB. It turns out that μord drops with increasing the Hubbard parameter, down to 2.28 μB at U = 4 and J = 1 eV. The careful analysis of the density of states (DOS) and the electronic band structure (EBS) reveals that Ba2TiMnO6 is a direct band gap semiconductor with a semiconducting energy gap of approximately Eg = 0.98 eV. The effects of U-J parameters were examined for Eg. We found that in opposite to μord, Eg shows an upward trend with U, reaching a value of 1.33 eV at U = 5 eV, J = 1 eV. We compared our findings to those found in the literature.

Electronic Structure and Optical Properties of Inorganic Pm3m and Pnma CsPbX3 (X = Cl, Br, I) Perovskite: A Theoretical Understanding from Density Functional Theory Calculations.

In this study, we investigated the optoelectronic properties of cubic (Pm3m) and orthorhombic (Pnma) CsPbX3 (X = I, Br, and Cl). We utilized the full potential linear augmented plane wave method, which is implemented in the WIEN2k code, to facilitate the investigation. Different exchange potentials were used to analyze the optoelectronic behavior using the available density functional theory methods. Our findings revealed that CsPbX3 perovskites display direct band gaps at the R and Г points for cubic (Pm3m) and orthorhombic (Pnma) structures, respectively. Among the exchange potentials, the mBJ-GGA method provided the most accurate results. These outcomes concurred with the experimental results. In both Pm3m and Pnma structures, interesting changes were observed when iodide (I) was replaced with bromine (Br) and then chlorine (Cl). The direct band gap at the R and Г points shifted to higher energy levels. Similarly, when I was replaced with Br and Cl, there was a noticeable decrease in the absorption coefficient, dielectric constants, refractive index, and reflectivity, in addition to a band gap shift to higher energy levels.

An ab initio investigation of LiCoBO3 as Li-ion battery cathode material

We give a first principles approach for the structural, electronic and magnetic properties of LiCoBO3 and CoBO3 in the monoclinic lattices. Along [001] direction, based on density functional theory approach and using Full Potential Linear Augmented Plane Wave (FP-LAPW) method, Polarized spin and spin–orbit coupling are included in calculations, and major spin was set up. The calculations were carried out using generalized gradient approximation (GGA) + an on-site Coulomb self-interaction correction potential (GGA + U). The magnetic and orbital moments are estimated. The U value was considered to be equal to 6 eV for Co atom. The average equilibrium voltage over a full cycle, of the LiCoBO3 battery is estimated from our FP-LAPW calculations. The capacity of a cell and energy density of LiCoBO3 were calculated. The compound LiCoBO3 is a semiconductor with average intercalation voltage 4.01 V. The voltage difference help promote electrochemical performance, which opens a window for Li-ion battery marketing application.

Electronic structure, thermodynamics, and thermoelectric properties of YxAl1−xN semiconductor alloys for new promising optoelectronics and energy conversion: Ab Initio study

Key characteristics such as structural, electronic, thermodynamic, and thermoelectric of wurtzite yttrium aluminum nitride (YxAl1−xN) semiconductor alloys (with 0≤ x ≤ 0.375) were investigated using Ab Initio density functional simulation within powerful full-potential linear augmented plane wave (FP‒LAPW) method. The equilibrium structural parameters (a0, c0, c0/a0,V0) were determined using the revised GGA−PBEsol approach in perfect agreement with experiments. The lattice a0-parameter varies almost linearly with yttrium concentration with a bowing of −0.08597 Å, while the c0-parameter has a bowing of −0.5715 Å. The lattice dynamics of doped YxAl1−xN systems were analyzed based on formation energy and phonon frequencies. Electronic structures of wurtzite YxAl1−xN described from a modern nKTB−mBJ potential show bandgap engineering with a range of [6.10 eV–3.85 eV] for x varies from 0 to 0.375, covering emission wavelengths [203 nm–322 nm] in the ultraviolet spectrum. The electron charge density contours indicate ionic bonding in wurtzite YxAl1−xN. Using the quasi-harmonic Debye model, thermodynamic properties of YxAl1−xN alloys, including volume (V0), mass modulus (B0), specific heat (Cv), thermal expansion (α), entropy (S), Debye temperature (ΘD) and Grüneisen parameter (γ), were calculated and analyzed under temperature and pressure effects. Moreover, electronic transport properties, such as the Seebeck coefficient (S), electrical conductivity (σ/τ), power factor, thermal conductivity (κel/τ), and figure of merit (ZT), of YxAl1−xN alloys were determined using BoltzTraP code. YxAl1−xN (at x = 0.25 and T = 600 K) exhibited the largest magnitude of S, with a value of ∼213.9 μV/K, and ZT ∼ 0.72. It also had the lowest value of κ/τ ∼9.9 × 1013 W m−1.K−1.s−1. Wurtzite YxAl1−xN crystal appears to be an extremely interesting candidate for potential applications in optoelectronics (UV) and future green energy system.

Electronic structure and optical properties of tin (IV) doped transparent perovskite crystal BaTiO3 for efficient visible optoelectronic devices and solar cells

The electronic structure and optical properties of BaSnxTi1−xO3 (BSnT, 0 ≤ x ≤ 0.375) perovskite crystals have been investigated using the newly developed PBEsol and nKTBmBJ approaches within the full potential linear augmented plane wave (FPLAPW) method for potential applications in optoelectronics. The lattice parameter showed a0 a quasi-linear increase with Sn content (with a bowing parameter of ∼ 0.048 Å). The calculated formation energy indicates that BSnT crystals are thermodynamically stable. BSnT exhibits a direct bandgap within the Sn composition range of ∼ 0.03–0.375, which can cover the emission wavelengths within the UV–visible spectrum region of ∼ 375–442 nm. The addition of Sn dopants into BaTiO3 results in a significant increase in the bandgap (by ∼ 496 meV, up to x = 0.375) due to the resonant interaction between O_2p orbitals and Sn_4d states in the upper valence band. Furthermore, the dielectric functions (ε1, ε2), refractive index n, extinction coefficient k, reflectivity R, and absorption coefficient α were determined for the radiation range of 0–12 eV and were found to be in close agreement with experimental spectra. BSnT exhibits good absorption within the ultraviolet spectrum while remaining transparent within the visible spectrum. Sn-doped BaTiO3 holds great promise as a transparent and/or active layer in the development of modern/low-cost solar cells and light-emitting diodes (LEDs) for visible light communication (VLC).

Elastic, electronic, thermal and magnetic investigations of PrX2(X = Fe,Ru) superconductors materials

The structural, elastic, electronic properties, thermal properties and magnetic hyperfine field and thermoelectric response of Laves phase PrFe2 and PrRu2 compounds are researched by using density functional theory via full-potential linear augmented plane waves (FP-LAPW) method within the local orbitals joining the generalized gradient approximation (GGA-PBESol) of exchange-correlation functional as applied in WIEN2k software package. Additionally, the semi-classical Boltzmann theory is utilized to investigate the stress behavior and superconductors applications on magnetic moments of each atom from 0 to 25 GPa for both materials are researched. The GGA-PBESol+U approximation is employed to address the f states of Pr atoms and d states of Fe and Ru atoms. The geometrical analysis of structural parameters is applied. The structural parameters calculated by two approximations are in a good agreement with other results. The calculated elastic constants, Young’s modulus, shear modulus, Poisson’s ratio, sound velocities and Debye temperature are investigated. The thermodynamic properties are calculated by a semi-harmonic Debye model in the pressure range, 0–25 GPa and temperature, 0–1000 K. The partial and total density of states (DOS) are investigated for PrFe2 and PrRu2 compounds. The partial DOS illustrates a hybridized strong at Fermi level. While, the hyperfine magnetic field is determined using two GGA-PBESol and GGA-PBESol+U approximations. Both PrFe2 and PrRu2 have superconducting critical temperatures; 550 K and 580 K, respectively. The comprehensive experimental characterization of PrRu2 is still absent in the literature and superconducting critical-temperature values are favorable with a similar experimental value; 530 K for PrFe2.

Electronic and optical properties of quaternary selenides for optoelectronic applications: Insights from DFT+U‐computations

AbstractThe optical properties, electronic charge density, electronic structure of the new layered selenides materials, BaGdCuSe3, CsUCuSe3, CsZrCuSe3, and CsGdZnSe3 compounds have been calculated by using the full potential and linear augmented plane wave (FP‐LAPW) methods as applied in the WIEN2k package, which is based on the density functional theory. The ALnMSe3 compound's structure of these was (A = Cs, Ba; Ln = Zr, Gd, U; M = Cu, Zn) is composed of (n = 1, 2) layers, which might be separated by A atoms. It is to be observed that there is strong hybridization between the s, p, and d states of Zr, Gd, and Cu atoms. Around the gadolinium atom, the charge density contours are completely circular, but the Gadolinium “Gd” atom shows an ionic nature. To calculate the refractive index, we used Kramer's Kronig correlations with the imaginary part dielectric function. The decrease in the refractive index is due to the lack of probability for direct excitation of the electrons, resulting in a loss of energy. The value of the static refractive index for all reference compounds is about 1.75–2.25, which is indication that the material used in optoelectronic devices.

Theoretical prediction of doping iron ions effect on the optoelectronic and magnetic cobalt-based perovskite (Co1-xFexScO3)

The ab-initio framework has taken place by means of the Full-potential Linear Augmented Plane-Wave (FP-LAPW) method, using the modified Becke-Johnson exchange potential approximation. This modified method was carried out to study the effects of doping iron ions on the structural, electronic, magnetic, and optical properties of CoScO3 perovskite compound. Doping Fe ions have formed a nonstoichiometric perovskite Co1-xFexScO3 where x = 0, 0.25, 0.50, 0.75, and 1. all doped compounds crystallized in a tetragonal lattice due to the Jahn-Teller effect, while the lattice constant was calculated and found to vary between the value of the two pure compounds. Meanwhile, the stabilities of the studied compounds are shown in the negative values of the formation energy. The magnetic moment was calculated and the whole compounds showed a ferromagnetic behavior. Co1-xFexScO3 perovskite is a potential candidate for spintronic application due to the presence of the half metallic behavior. All optical spectrums including dielectric function, absorption coefficient, reflectivity and refractivity index, and energy loss function show remarkable features for the proposed perovskites.

Mechanical, thermal, electronic, and magnetic properties of Ca0.75Er0.25S alloy from a DFT approach: A promising material for spintronic applications

This paper presents a systematic study of the calculated mechanical properties, electronic structures and magnetic moments of dilute magnetic semiconductor Ca1−xErxS (x = 25 %) using the density functional theory (DFT)-based the full potential linear augmented plane-wave (FP-LAPW) method. The exchange and correlation potential is treated by the generalized gradient approximation GGA-PBE frameworks, which are utilized to characterize the structural and elastic properties of Ca1−xErxS. Moreover, the GGA-PBE +U and mBJ-PBE+U were also applied for the electronic and magnetic properties. To understand magnetic ground state the energy difference in ferromagnetic (FM) and anti-ferromagnetic (AFM) configurations was calculated. The calculated band structure improves when GGA-PBE+U and the modified Becke-Johnson approach (mBJ-PBE+U) methods are employed. The electronic structure analysis reveals that GGA-PBE predicts Ca1−xErxS ternary alloy to be metallic while GGA-PBE +U and mBJ-PBE+U predicts it to be half metallic ferromagnetic with 100 % spin-polarization at the Fermi level, with magnetic moment of 2 μB per formula unit and a band gap 1.90 and 2.40 eV, respectively. Our results indicate that identical magnetic ground states are obtained GGA-PBE +U and mBJ-PBE+U and the magnetic moment mainly arises from 4 f of Erbium (Er). To our knowledge, this is the first time that the physical properties of Ca0.75Er0.25S have been reported, and with consequence the present results can provide the data support for experimental and other theoretical investigations.

Physical characteristics of X2NaMoBr6 (X= K, Rb): A DFT study

The full-potential linearized-augmented plane-wave (FP-LAPW) method based on density functional theory (DFT) was used to investigate the structural, elastic, electronic, optical, magnetic and thermoelectric (TE) characteristics of halide double-perovskites (HDPs) X2NaMoBr6 (X = K, Rb). Perdew, Burke and Ernzerhof generalized-gradient approximation (PBEsol-GGA) + modified Becke-Johnson (mBJ) potential were employed. Enthalpy of formation (ΔH) was found to be −3.243 eV for K2NaMoBr6 and -3.209 for Rb2NaMoBr6 which (negative values) confirm the stability of the compounds. The ferromagnetic behaviour was identified from the integer values of the total magnetic-moment (μB) which were 3.00001 and 3.00002 for K2NaMoBr6 and Rb2NaMoBr6, respectively. Moreover, the value of static dielectric constant ε1(0) was found to be 3.21 for K2NaMoBr6 and 3.27 for Rb2NaMoBr6. TE characteristics were calculated by using Boltztrap code. Both compounds showed the absorption in the UV region (6.86 eV for Rb2NaMoBr6 and 7.11 eV for K2NaMoBr6). Results indicate that both X2NaMoBr6 (X = K, Rb) compounds are appropriate candidates for TE, optical and data storage applications.

Study of the magnetic properties of LiMn1.5Ni0.5O4 spinel: Ab initio calculation and Monte Carlo simulation

In the present work, the Ab initio calculations, based on Density Functional Theory with the Hubbard correction U (DFT + U) approach and Full potential Linear Augmented Plane Wave (FLAPW) method are used to calculate the exchange integrals for Lithium-Nickel-Manganese Oxide LiMn1.5Ni0.5O4. The exchange integrals values JMn-Mn, JNi-Ni and JMn-Ni are obtained by substituting the totalenergiesof different magneticground states configurationinto theIsing model. Those values are used as input for Monte Carlo simulations to study the magnetization as a function of temperature and external magnetic field for several values of U.

Structural, Electronic, Magnetic and Mechanical Properties and Magnetocaloric Effect of the Full-Heusler Co2MnGa

Structural, electronic, magnetic and mechanical properties of the Co2MnGa have been calculated with functional density theory using full potential linear augmented plane wave method as implemented in the Wien2k code. Exchange correlation effects for these properties are treated by generalized gradient approximation while for electronic and magnetic properties, in addition to (WC-GGA) correction, mBJ-GGA scheme was also applied. The stiffness constant of the spin wave and the Curie temperature are calculated. Moreover, mechanical parameters included three elastic constants, compression modulus, Young’s modulus and shear modulus are also investigated. This theoretical study provides detailed information on the compound Co2MnGa, in different aspects and can also provide information on the application of this material. Obtained data from ab initio calculations are used as input for Monte Carlo simulations to study the magnetic properties and magnetocaloric effect. Transition temperature, magnetic entropy change, adiabatic temperature change and relative cooling power were found.