Tunable Multi-Level Memory States in Compositionally Graded Lead-Free Ferroelectric Thin Films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Ferroelectric memories offer high speed and low power for in-memory and neuromorphic computing.
• Achieving reliable multistate polarization is a key challenge due to ferroelectric switching bi-stability.

Purpose of the Study:

• To demonstrate robust multistate polarization states in ferroelectric thin films.
• To investigate the mechanism behind multistate behavior and control it via compositional engineering.

Main Methods:

• Fabrication of compositionally graded BiFeO3-BaTiO3 epitaxial thin films.
• Characterization of ferroelectric properties using hysteresis loops and domain switching analysis.
• Correlation of defect dipole configuration with compositional gradients.

Main Results:

• Demonstrated robust multi-level polarization states with antiferroelectric-like hysteresis loops.
• Observed well-separated switching fields and large polarization contrast (ΔP > 40 µC/cm²).
• Identified pinning of ferroelectric domains by defect dipoles as the cause of multistate behavior.

Conclusions:

• Compositional gradient engineering provides deterministic control over multiple stable ferroelectric states.
• This strategy tailors ferroelectric energy landscapes for adaptive memory and neuromorphic applications.
• Paves the way for high-density, low-power ferroelectric memory and neuromorphic architectures.