Creating multiferroics with large tunable electrical polarization from paraelectric rare-earth orthoferrites

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Developing materials with high-temperature magnetic ordering and large electrical polarization is crucial for spintronic and memory devices.
• Bismuth ferrite (BiFeO3) and related compounds are currently the only known materials exhibiting these dual properties.

Purpose of the Study:

• To explore rare-earth orthoferrites (RFeO3) as potential multiferroic materials.
• To investigate the effects of epitaxial strain on the magnetic and electrical properties of RFeO3 films.

Main Methods:

• First-principles calculations were employed to predict the behavior of RFeO3 under various strain conditions.
• The study focused on analyzing the emergence of ferroelectricity and multiferroicity in response to applied strain.

Main Results:

• Epitaxial RFeO3 films are predicted to become ferroelectric and multiferroic under sufficient strain.
• High compressive strain can lead to a tetragonal ferroelectric phase with giant polarization in RFeO3 with large rare-earth ions.
• Large tensile strain may induce novel inhomogeneous ferroelectric phases with significant polarization.
• A multiphase boundary exists, offering opportunities for property optimization.

Conclusions:

• Rare-earth orthoferrites represent a promising new class of multiferroic materials.
• Epitaxial strain offers a tunable pathway to engineer the multiferroic properties of RFeO3.
• These findings could pave the way for next-generation spintronic and memory devices.