Tailoring polarization homogeneity in discontinuous-columnar Bi(Fe,Mn)O₃ thin films via dislocation engineering with...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Defect microstructures, especially dislocations, critically influence ferroelectric thin film properties.
• The spatial configuration of dislocations, unlike their density, is poorly understood and challenging to control.

Purpose of the Study:

• To develop a controlled self-assembly strategy for dislocations in bismuth iron manganese oxide (Bi(Fe,Mn)O3) thin films.
• To investigate how ordered dislocation microstructures impact ferroelectric properties and aging stability.

Main Methods:

• Utilized a lanthanum nickel oxide (LaNiO3) buffer layer to template a discontinuous-columnar grain structure.
• Guided the self-assembly of edge dislocations along grain boundaries in a topologically-protected configuration.
• Analyzed the resulting microstructure, strain fields, octahedral tilting, polarization homogeneity, and domain behavior.

Main Results:

• Achieved ordered dislocation microstructures through a novel self-assembly strategy.
• Demonstrated enhanced polarization homogeneity, reduced domain-switching barriers, and uniform domain pinning.
• Bi(Fe,Mn)O3 thin films showed superior aging stability, with significantly smaller reductions in remanent polarization and coercive field after 60 days at 60°C.

Conclusions:

• Established a defect engineering paradigm leveraging deliberate dislocation rearrangement.
• Showcased a method to unlock superior ferroelectric performance and stability in thin films.
• The findings pave the way for designing advanced ferroelectric materials with tailored properties.