Ab-initio analysis of magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6 manganite

Perovskite-like materials, which include magnetic elements, have relevance because their technological perspectives of applications in the spintronics industry. In this work, the magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6 of the perovskite-like manganite are investigated. Calculations are carried out through the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) with exchange and correlation effects in the Generalized Gradient (GGA) and Local Density (LDA) approximations, including spin polarization. From the minimization of energy as a function of volume using the Murnaghan’s state equation the equilibrium lattice parameter and cohesive properties of this compound were obtained. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the band structure, showing that this compound evidences an effective magneticmoment of 3.0 μB. The pressure and temperature dependence of specific heat, entropy, thermal expansion coefficient, Debye temperature and Grüneisen parameter were calculated by DFT from the state equation using the quasi-harmonic model of Debye. A specific heat behavior CV≈CP was found at temperatures below T = 400 K, with Dulong-Petit limit values, which are quite higher than those, reported for simple perovskites.Los materiales de tipo perovskita que incluyen elementos magnéticos son relevantes debido a sus perspectivas de aplicabilidad tecnológica en la industria de la espintrónica. En este trabajo fueron investigadas las propiedades magnéticas, estructurales, electrónicas y termodinámicas de la manganita de tipo perovskita Ba2TiMnO6. Los cálculos fueron realizados a través del método del potencial de ondas planas aumentadas y linealizadas (FP-LAPW), en el marco de la Teoría del Funcional Densidad (DFT), con efectos de intercambio y correlación en las aproximaciones de gradiente generalizado (GGA) y de densidad local (LDA), incluyendo polarización de espín. A partir de la minimización de la energía en función del volumen, usando la ecuación de estado de Murnaghan se obtuvieron los parámetros de equilibrio de la red las propiedades de cohesión de este compuesto. El estudio de la estructura electrónica se basó en el análisis de la densidad de estados (DOS) y la estructura de bandas, mostrando que este compuesto evidencia un momento magnético efectivo de 3.0 μB. la dependencia con la temperatura y la presión del calor específico, la entropía, el coeficiente de expansión térmica, la temperatura de Debye y el parámetro de Grüneisen fueron calculados mediante DFT a partir de la ecuación de estado, usando el modelo cuasi-armónico de Debye. Se encontró que el calor específico CV≈CP para temperaturas por debajo de T = 400 K, con un límite de Dulong-Petit relativamente mayor que el reportado para perovskitas simples

Ground state structural, lattice dynamic, thermodynamic and optical properties of the Ba₂CaMoO₆ ordered perovskite

Ab-initio calculations based on density functional theory have been performed to establish the ground state properties for the double perovskite type material Ba₂CaMoO₆. The calculations were carried out through the Projector Augmented Wave Method and the exchange and correlation was described using the Perdew-Burke- Ernzerhof parameterization of the Generalized Gradient Approximation. The study included structural analysis of the material, as well as thermodynamic, cell dynamics and optical properties at its transition between the tetragonal I4/m and cubic Fm 3 m phases. The results on the structural stability reveal that the phase with space group of I4/m is more stable. Likewise, the structural phase transition was obtained for a pressure of 0.067 GPa. On the other hand, the analysis of the electronic properties shows that the material presents a semiconducting behaviour, with a direct band gap of 2.40 eV and 2.26 eV for the tetragonal and cubic structures, respectively. In addition to agreeing with the experimental values reported in the literature, the results suggest possibilities for the application of this material in photodetectors, light emitters and devices for power electronics.Instituto de Física La Plat

Ab-initioanalysis of magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6 manganite

Perovskite-like materials, which include magnetic elements, have relevance because their technological perspectives of applications in the spintronics industry. In this work, the magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6of the perovskite-like manganite are investigated. Calculations are carried out through the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) withexchange and correlation effects in the Generalized Gradient (GGA) and Local Density (LDA) approximations, including spin polarization. From the minimization of energy as a function of volume using the Murnaghan’s state equation the equilibrium lattice parameter and cohesive properties of this compound were obtained. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the band structure, showing that this compound evidences an effective magneticmoment of 3.0 μB. The pressure and temperature dependence of specific heat, entropy, thermal expansion coefficient, Debye temperature and Grüneisenparameter were calculated by DFT from the state equation using the quasi-harmonic model of Debye. A specific heat behavior CV≈CPwas found at temperatures below T = 400 K, with Dulong-Petit limit values, which are quite higher than those, reported for simple perovskites.Los materiales de tipo perovskitaque incluyen elementos magnéticos son relevantes debido a sus perspectivas de aplicabilidad tecnológica en la industria de la espintrónica. En este trabajo fueron investigadas las propiedades magnéticas, estructurales, electrónicas y termodinámicas de la manganita de tipo perovskita Ba2TiMnO6. Los cálculos fueron realizados a través del método del potencial de ondas planas aumentadas y linealizadas (FP-LAPW), en el marco de la Teoría del Funcional Densidad (DFT), con efectos de intercambio y correlación enlas aproximaciones de gradiente generalizado (GGA) y de densidad local (LDA), incluyendo polarización de espín. A partir de la minimización de la energía en función del volumen, usando la ecuación de estado de Murnaghan se obtuvieron los parámetros de equilibrio de la red las propiedades de cohesión de este compuesto. El estudio de la estructura electrónica se basó en el análisis de la densidad de estados (DOS) y la estructura de bandas, mostrando que este compuesto evidencia un momento magnético efectivo de 3.0 μB. la dependencia con la temperatura y la presión del calor específico, la entropía, el coeficiente de expansión térmica, la temperatura de Debye y el parámetro de Grüneisen fueron calculados mediante DFT a partir de la ecuación de estado, usando el modelo cuasi-armónico de Debye. Se encontró que el calor específico CV≈CPpara temperaturas por debajo de T = 400 K, con un límite de Dulong-Petit relativamente mayor que el reportado para perovskitas simples

Electronic, structural and ferroelectric properties of the ba2zrtio6 double perovskite

We report the synthesis, the structural characterization, the ferroelectric behavior and the electronic properties of complex perovskite Ba2ZrTiO6. Samples of Ba2ZrTiO6 were synthesized through the standard solid state reaction method. The crystalline structure was studied by means of X-ray diffraction experiments and Rietveld-like analysis. Results reveal that the material crystallizes in a rhomboidal structure, space group R-3 (#148), with cell parameter a=5.8038(7) Å. The ferroelectric response of material was established from curves of polarization as a function of applied electric field. Our results reveal that the double perovskite Ba2ZrTiO6 has a ferroelectric hysteretic behavior at room temperature. The studies of the electronic structure show that Ba2ZrTiO6 behaves as a nonmetallic material with gap energy 2.32 eV. The structural parameters obtained from energy minimization, through the Murnaghan equation state are 99.5% in agreement with the experimental data

Ab-initio analysis of magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6 manganite

Perovskite-like materials, which include magnetic elements, have relevance because their technological perspectives of applications in the spintronics industry. In this work, the magnetic, structural, electronic and thermodynamic properties of the Ba2TiMnO6 of the perovskite-like manganite are investigated. Calculations are carried out through the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) with exchange and correlation effects in the Generalized Gradient (GGA) and Local Density (LDA) approximations, including spin polarization. From the minimization of energy as a function of volume using the Murnaghan’s state equation the equilibrium lattice parameter and cohesive properties of this compound were obtained. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the band structure, showing that this compound evidences an effective magneticmoment of 3.0 μB. The pressure and temperature dependence of specific heat, entropy, thermal expansion coefficient, Debye temperature and Grüneisen parameter were calculated by DFT from the state equation using the quasi-harmonic model of Debye. A specific heat behavior CV≈CP was found at temperatures below T = 400 K, with Dulong-Petit limit values, which are quite higher than those, reported for simple perovskites

Thermodynamic evidence of the ferroelectric Berry phase in europium-based ferrobismuthite Eu₂Bi₂Fe₄O₁₂

The possible low temperature biferroic feature of Eu₂Bi₂Fe₄O₁₂ complex perovskites was recently reported. The aim of this work is to present a theoretical study of the structural, magnetic, electronic and ferroelectric properties of this material. Several energy minimization processes were performed for three types of cationic distributions, different angles of rotation, octahedral inclination, and some kinds of magnetic ordering. The results reveal that the most stable crystallographic arrangement corresponds to an intercalated distribution of the Eu³⁺ and Bi³⁺ cations between the FeO₆ octahedra. Similarly, energy is minimized for rotations and octahedral inclinations corresponding to angles θₑ = 12.86° and ϕₑ = 13.32°, respectively. With respect to the distribution of magnetic moments, the results reveal that a G-type antiferromagnetic configuration is the most energetically favorable. The electronic structure is studied from ab initio calculations following the formalism of density functional theory and the pseudopotential plane wave method. In this formalism, the exchange and correlation mechanisms are described by means of the generalized gradient approach (GGA + U), considering spin polarization. The ferroelectric characteristic is analysed by determining ferroelectric polarization based on the calculation of the Berry phase. The theoretical results obtained are consistent with the experimental reports, which is why the Eu₂Bi₂Fe₄O₁₂ material is expected to exhibit biferroic behavior at low temperatures, because the Berry phase introduces hybridizations between the 3d-Fe and 2p-O states that favor the occurrence of Dzyaloshinskii-Moriya interactions, which facilitate the occurrence of ferroelectricity coexisting with weak ferromagnetism. An extensive study of the thermodynamic properties in the presence and absence of the Berry phase is undertaken by means of the Debye quasi harmonic model. The specific heat difference with and without the Berry phase reveals the occurrence of a ferroelectric transition at T = 113 K without the application of external pressure. When the applied pressure is incremented, a systematic increase in the transition temperature is observed due to the reduction of overlap between the 3d-Fe orbitals and the 2p-O orbitals in the compressed octahedra of perovskite.Facultad de Ciencias ExactasInstituto de Física La Plat