Multiscale structure of LaAlO₃ from single-crystal X-ray diffraction.

Area of Science:

• Materials Science
• Crystallography
• Solid State Physics

Background:

• Lanthanum aluminate (LaAlO3) exhibits complex domain structures crucial for its properties.
• Understanding domain wall behavior is key for materials engineering and device applications.

Purpose of the Study:

• To investigate the temperature-dependent domain behavior in LaAlO3 pseudo-merohedral twin crystals.
• To establish a method for calibrating unit-cell parameters from twin crystal data.
• To determine multiscale structural information from a single crystal.

Main Methods:

• Synchrotron single-crystal X-ray diffraction (XRD) on a LaAlO3 pseudo-merohedral twin crystal.
• Combined analysis with powder XRD data from the same sample.
• Domain-resolved structure analysis and unit-cell parameter calibration.

Main Results:

• Domain wall movement was observed in the temperature range of 450–700 K, consistent with mechanical measurements.
• Domain ratios approached equal distribution (25%) just below the phase transition temperature.
• The domain structure after heating to 840 K was found to be intrinsic to the crystal.

Conclusions:

• The study successfully determined multiscale structure information from a single LaAlO3 crystal.
• A novel method for unit-cell parameter calibration from twin crystal data was developed.
• Findings are significant for domain engineering and theoretical studies of LaAlO3.