Low-temperature topotactic oxidation using the solid-state oxidant Zr-doped CeO₂.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Superconductivity

Background:

• The anti-ThCr2Si2 structure type, exemplified by Y2O2Bi, can exhibit superconductivity through oxygen intercalation.
• Conventional solid-state oxidation for oxygen intercalation in Y2O2Bi requires high temperatures (1000 °C).
• High-temperature processing can lead to the segregation of undesirable impurity phases, hindering optimal material properties.

Purpose of the Study:

• To develop a novel topotactic oxidation method for Y2O2Bi.
• To achieve oxygen intercalation at significantly lower temperatures.
• To enhance the superconducting transition temperature of Y2O2Bi and prevent impurity phase formation.

Main Methods:

• Development of a new topotactic oxidation technique.
• Utilizing zirconium-doped cerium dioxide (Zr-doped CeO2) as a solid-state oxidant.
• Processing Y2O2Bi under specific conditions at 200 °C.

Main Results:

• Successful oxygen intercalation into Y2O2Bi was achieved at a much lower temperature (200 °C).
• The low-temperature topotactic oxidation effectively prevented the segregation of impurity phases.
• The highest superconducting transition temperature reported to date for Y2O2Bi was obtained using this method.

Conclusions:

• The developed topotactic oxidation method offers a more efficient route to intercalate oxygen into Y2O2Bi.
• Lower processing temperatures are beneficial for achieving high-quality superconducting materials by avoiding impurity formation.
• This advancement provides a pathway to optimize the superconducting properties of Y2O2Bi and related materials.