Stuffed Tridymite Structures: Synthesis, Structure, Second Harmonic Generation, Optical, and Multiferroic Properties

The stuffed tridymite structure Ba(Zn/Co)(1-x)Si1-xM2xO4 (M=Al3+ and Fe3+) is explored for the possible multiferroic behavior and to develop new inorganic colored materials. The compounds were synthesized by employing conventional solid-state chemistry methods in the temperature range 1100-1175 degrees C for 24 h. The powder X-ray diffraction (PXRD) and Rietveld refinement studies indicate that the compounds stabilize in the P63 space group (no. 173). The refinement results were also rationalized by employing Raman spectroscopic studies. The compounds were found to be second harmonic generation (SHG) active and show weak ferroelectric behavior. The co-substitution of Co2+ and Fe3+ in the structure gives rise to a weak ferromagnetic behavior to the compound, BaCo0.75Si0.75Fe0.5O4, making it a multiferroic material. The optical studies on the prepared compounds exhibited blue color (Co2+ in T-d geometry), purple color (Ni2+ in T-d geometry), and simultaneous substitution of Co2+ and Fe3+ gives rise to blue-green color owing to metal-to-metal charge transfer (MMCT) effect.

Automated summary

In this study, the stuffed tridymite structure Ba(Zn/Co)(1-x)Si1-xM2xO4 (M=Al3+ and Fe3+) was synthesized and explored for possible multiferroic behavior, leading to the development of new inorganic colored materials. A compound BaCo0.75Si0.75Fe0.5O4 was identified as a multiferroic material with weak ferromagnetic behavior. Optical studies revealed different colors based on the metal ions and charge transfer effects in the compounds.