Molten salt flux synthesis of cobalt doped refractory double perovskite Sr 2CoxGa1-xNbO6: A spectroscopic investigation for multifunctional materials

A simple and cost-effective salt synthesis route toward refractory oxides of composition Sr 2Ga1-xCoxNbO6 has been carried out. Herein, we report on the refinement of the set of parameters related to heat treatment to stabilize the ordered perovskite for cobalt content, x, ranging from 0.02 to 0.2. The parameters studied were the nature of the flux, the dwell temperature, the dwell time and the cooling rate for a given cobalt precursor. Our study relied on powder X-ray diffraction, UV-visible-near IR (UV-vis-NIR), Electron Spin Resonance (ESR) and Nuclear Magnetic Resonance (NMR) experiments allowing us to better understand the room temperature electronic structure. The tuning of energy gap with the cobalt content, mixed spin state Co3+ (Low Spin + Intermediate/High Spin) at room temperature and the brown shades of these materials render them the multifunctionality.

Automated summary

A simple and cost-effective synthesis method using salt has been employed to synthesize a refractory oxide Sr2Ga1-xCoxNbO6. By adjusting the heat treatment parameters, the ordered perovskite structure for different cobalt contents (x from 0.02 to 0.2) has been stabilized. The room temperature electronic structure has been investigated through various experiments, revealing the tunability of energy gap, mixed spin states, and brown coloration in these materials.