High Entropy Oxide Relaxor Ferroelectrics

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Relaxor ferroelectrics exhibit valuable properties like strong electromechanical response and energy storage.
• Current material design often relies on subtle compositional changes, limiting performance.
• Discovering new relaxor ferroelectrics is crucial for advanced technological applications.

Purpose of the Study:

• To explore relaxor ferroelectric behavior in highly compositionally complex perovskites.
• To synthesize and characterize single-crystal Ba(Ti0.2Sn0.2Zr0.2Hf0.2Nb0.2)O3 [Ba(5B)O] films.
• To investigate the impact of configurational disorder on ferroelectric properties.

Main Methods:

• Entropy-assisted synthesis of single-crystal Ba(5B)O films.
• Temperature-dependent dielectric, Raman spectroscopy, and second-harmonic generation measurements.
• First-principles theory calculations for predicting new material compositions.

Main Results:

• Successful synthesis of single-crystal Ba(5B)O films with high configurational disorder.
• Observation of multiple phase transitions, a high Curie temperature (570 K), and relaxor ferroelectric behavior.
• Demonstration that strong compositional complexity stabilizes relaxor responses.

Conclusions:

• Highly disordered perovskites can exhibit stable relaxor ferroelectric properties.
• This approach offers a new pathway for designing high-performance ferroelectric materials.
• Ba(5B)O films show potential for piezoelectric, pyroelectric, and electrocaloric applications.