RESUMO
Low loss Ruddlesden-Popper (RP) series, i.e., (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06, has been synthesized by a mixed oxide route. In this work, the substitution of Ca2+ cation in Sr5Ti4O13 sintered ceramics was chosen to enhance the structural, optical, and dielectric properties of the product. It was found that the Ca2+ content has significant effects on enhancing the dielectric properties as compared to Mn and glass additions. It was observed that the relative density, band gap energy, and dielectric loss (tangent loss) increase while relative permittivity decreases along with Ca2+ content. High relative density (96.7%), low porosity, and high band gap energy (2.241 eV) values were obtained in (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06 sintered ceramics. These results will play a key role in the application of dielectric resonators.
RESUMO
This study reports the theoretical investigations on the structural, electronic, and optical properties of titanium-based fluoro-perovskites MTiF3 (M = Cs and Rb) using density functional theory. The impact of on-site Coulomb interactions is considered, and calculations are performed in generalized gradient approximation with the Hubbard U term (GGA + U). The ground state parameters, such as lattice constants, bulk modulus, and pressure derivatives of bulk modulus, were found. These compounds are found stable in cubic perovskite structures having lattice constants of 4.30 and 4.38 Å for RbTiF3 and CsTiF3, respectively. Analysis of elastic properties shows that both of the compounds are ductile in nature. According to the band structure profile, the examined compounds have a half-metallic character, exhibiting conducting behavior in the spin-up configuration and nonconducting behavior in the spin-down configuration. The ferromagnetic nature is conformed from the study of its magnetic moments. The optical behaviors such as reflectivity, absorption, refraction, and conductivity of the cubic phase of MTiF3 (M = Rb and Cs) are studied in the energy range of 0-40 eV.
