Abstract
The current work describes the synthesis, structure, magnetic and optical properties of Cu1+ based delafossite oxides, Cu3(MFeSb)O6 (M = Na, Li) synthesized by the topotactic ion-exchange reactions (around 400 °C) of CuCl with Na4FeSbO6 and Na3LiFeSbO6 in an inert argon atmosphere. The synthetic procedure is significant as the oxides could not be synthesized by the solid state methods. Chemical analysis coupled with energy dispersive spectral analysis confirmed the extent of replacement of Na+ ions by Cu+ ions. A complete exchange of alkali metal ion, Na+ by Cu1+ in the interlayers of these honeycomb oxides has been achieved using a ratio of 1:3 between Na4FeSbO6 and CuCl. An additional exchange of approximately 70 % Na+ ions from the honeycomb arrays is possible by varying the ratio to 1:4. Rietveld refinements (space group C2/c) of the powder X-ray diffraction data have been carried out to ascertain the phase purity and to verify the structure formed by edge shared honeycomb arrays separated by Cu1+ in dumbbell configuration (O–Cu1+-O). X-ray photoelectron spectroscopy analysis confirmed the oxidation states of the constituent ions, specifically copper as Cu1+. A similar method is adopted to synthesize Cu3(LiFeSb)O6 by reacting Na3(LiFeSb)O6 and CuCl in the ratio 1:3 at 400 °C. These new delafossite oxides, Cu3(MFeSb)O6 (M = Na, Li) and Cu3((Cu0.7Na0.3)FeSb)O6, exhibit interesting magnetic properties which are significantly different from the rock salt based parent sodium analogs. Dominant antiferromagnetic interactions with a specific ordering temperature have been observed for these samples containing Fe3+ (d5) ions in the honeycomb. UV–visible diffuse reflectance measurements indicated the decrease in the band gap of Cu1+ based oxides. This study highlights the importance of low temperature ion-exchange reactions as an effective route to stabilize multifunctional materials of potential importance for various applications.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
