Room-temperature skyrmion phase in bulk Cu₂OSeO₃ under high pressures

Area of Science:

• Condensed Matter Physics
• Materials Science
• Magnetism

Background:

• Skyrmion states in noncentrosymmetric helimagnets offer unique topological spin textures with significant technological potential.
• The equilibrium skyrmion phase is typically confined to a narrow temperature range near the magnetic transition temperature (Tc), limiting practical applications.

Purpose of the Study:

• To expand the skyrmion phase region in single-crystalline Cu2OSeO3 to higher temperatures and wider magnetic field ranges.
• To investigate the influence of high pressure on skyrmion stability and phase transitions in helimagnetic materials.

Main Methods:

• Utilized an ultrasensitive high-pressure magnetization technique to study single-crystalline Cu2OSeO3 up to 42.1 GPa.
• Analyzed pressure-induced phase transitions from cubic to orthorhombic, monoclinic, and triclinic crystal structures.
• Performed Ginzburg-Landau free energy analyses to understand the stabilization mechanisms of skyrmion states.

Main Results:

• Successfully expanded the skyrmion phase region from 55–58.5 K to 5–300 K under pressures up to 42.1 GPa.
• Observed that applied pressure stabilizes skyrmion states, particularly at higher temperatures.
• Demonstrated that skyrmion states can be achieved across various crystal symmetries, indicating robustness.

Conclusions:

• High pressure is an effective method for stabilizing and expanding the skyrmion phase in helimagnets.
• Skyrmions exhibit remarkable stability across different crystal structures, suggesting their potential ubiquity in helimagnetic systems.
• This work paves the way for realizing skyrmion-based technologies at higher operating temperatures.