We investigate the electronic and magnetic properties of Ca2CrIrO6 and Ca2FeIrO6 by means of density functional theory. These materials belong to a family of recently synthesized Ca2CrOsO6 whose properties show possible applications in a room temperature regime. Upon replacement of Os by Ir in Ca2CrOsO6, we found the system to exhibit a stable ferrimagnetic configuration with a bandgap of ∼0.25 eV and an effective magnetic moment of ∼2.58μB per unit cell. Furthermore, when chemical doping is considered by replacing Cr with Fe and Os with Ir, the material retains the insulating state but with a reduced bandgap of 0.13 eV and large increment in the effective magnetic moment of ∼6.68μB per unit cell. These observed behaviors are noted to be the consequence of the cooperative effect of spin–orbit coupling; Coulomb correlations from Cr-3d, Fe-3d, and Ir-5d electrons; and the crystal field effect of the materials. These calculations suggest that by chemical tuning, one can manipulate the bandgap and their effective magnetic moment, which may help in material fabrication for device applications. To check further the suitability and applicability of Ca2CrIrO6 and Ca2FeIrO6 at higher temperatures, we estimate the Curie temperature (TC) by calculating the spin–exchange coupling. We found that our findings are in a valid TC trend similar to other perovskites. Our findings are expected to be useful in experimental synthesis and transport measurement for potential applications in modern technological devices.

Using the density functional theory formalism, electronic and magnetic properties of double perovskites Ca2MnIrO6  are investigated. We found ferrimagnetic ground state with half-metallic nature in Ca2MnIrO6. The electron-correlation, crystal distortion, and spin-orbit coupling (SOC) plays significant role in dictating the electronic properties in this system. From the density of states calculations, a strong hybridization were noted between O-2p, Ir-5d and Mn-3d states resulting Ca2MnIrO6 to half-metal (HM) with metallic state in spin up channel and insulating state in spin-down channel.  The HM state persists even when SOC is taken into account, though the spin-polarization reduces slightly. We thus predict Ca2MnIrO6  as a new HM ferrimagnet which can be useful for modern technological applications. We further investigated the Curie temperature of Ca2MnIrO6  by calculating the spin-exchange coupling parameters. Our results are found to be comparable with other perovskites. BIBECHANA 19  (2022) 127-132

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