Automated detection and mapping of crystal tilt using thermal diffuse scattering in transmission electron microscopy

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Quantitative analysis of crystalline specimens using transmission electron microscopy (TEM) relies on accurate local crystal orientation.
• Determining precise crystal orientation is crucial for understanding material properties and behavior.

Purpose of the Study:

• To develop and validate a method for accurately determining local crystal orientation from momentum-resolved scanning TEM (STEM) data.
• To enable precise crystallographic tilt and in-plane rotation mapping in various materials.

Main Methods:

• Exploits momentum-resolved STEM data and geometric analysis of Kikuchi bands within diffraction patterns.
• Determines the center of the Laue circle to quantify local mistilt from major zone axes.
• Utilizes unit-cell averaged diffraction patterns from high-resolution STEM settings.

Main Results:

• Achieved an accuracy of approximately 0.1 mrad in simulation studies.
• Successfully implemented the method in automated software for experimental application.
• Generated orientation maps for high-Mn steel and a La_0.7Sr_0.3MnO₃-SrTiO₃ interface.

Conclusions:

• The developed method provides accurate and consistent crystallographic tilt mapping over large fields of view (>100 nm) with unit-cell resolution.
• This technique significantly improves the quantitative interpretation of TEM data for crystalline materials.
• The findings are applicable to diverse crystalline specimens, including advanced alloys and epitaxial thin films.