Ferroelastic domain identification in BiFeO₃ crystals using Raman spectroscopy

Area of Science:

• Condensed Matter Physics
• Materials Science
• Crystallography

Background:

• Multiferroic materials exhibit multiple ferroic orders, making them promising for advanced electronic devices.
• Bismuth Ferrite (BiFeO3) is a notable multiferroic material with complex domain structures.
• Understanding domain behavior is crucial for harnessing BiFeO3's properties.

Purpose of the Study:

• To investigate the symmetry and distribution of ferroelastic domains in multiferroic BiFeO3 crystals.
• To determine the orientation and characteristics of domain walls using micro-Raman spectroscopy.
• To correlate Raman spectroscopy findings with other crystallographic techniques.

Main Methods:

• Micro-Raman spectroscopy was employed using both resonant (442 nm) and non-resonant (633 nm) laser wavelengths.
• Azimuthal angle dependence of Raman mode intensities was analyzed for symmetry assignment.
• Raman tensor formalism was used for simulation and data interpretation.
• Line scans and mappings were performed to identify ferroelastic domain patterns.
• Electron backscattering diffraction (EBSD) was used for comparative analysis.

Main Results:

• Raman mode symmetries were successfully assigned based on azimuthal angle dependence.
• Ferroelastic domain patterns were identified and mapped using anisotropic intensity variations of polar Raman modes.
• Line scans at different wavelengths revealed a tilt in domain walls relative to the sample surface.
• Raman spectroscopy results showed excellent agreement with EBSD findings.

Conclusions:

• Micro-Raman spectroscopy is an effective tool for characterizing domain structures in multiferroic BiFeO3.
• The study confirms the presence of tilted domain walls in BiFeO3 crystals.
• The findings provide valuable insights into the complex interplay of ferroic orders and domain structures in BiFeO3.