Electronic, magnetic, optical and thermoelectric properties of Ca₂Cr_1-x Ni _x OsO₆ double perovskites.

ABSTRACT: With the help of density functional theory calculations, we explored the recently synthesized double perovskite material Ca₂CrOsO₆ and found it to be a ferrimagnetic insulator with a band gap of ∼0.6 eV. Its effective magnetic moment is found to be ∼0.23 μ _B per unit cell. The proposed behavior arises from the cooperative effect of spin-orbit coupling and Coulomb correlation of Cr-3d and Os-5d electrons along with the crystal field. Within the ferrimagnetic configuration, doping with 50% Ni in the Cr-sites resulted in a half-metallic state with a total moment of nearly zero, a characteristic of spintronic materials. Meanwhile, the optical study reveals that both ε ₁ ^xx and ε ₁ ^zz decrease first and then increase rapidly with increasing photon energy up to 1.055 eV. We also found optical anisotropy up to ∼14 eV, where the material becomes almost optically isotropic. This material has a plateau like region in the σ _xx and σ _zz parts of the optical conductivity due to a strong 3d-5d interband transition between Cr and Os. In addition, we performed thermoelectric calculations whose results predict that the material might not be good as a thermoelectric device due to its small power factor.

SUBMITTER: Bhandari SR 

PROVIDER: S-EPMC9059137 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature