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Exploring the structural complexity of intermetallic compounds by an adaptive genetic algorithm.
X Zhao1, M C Nguyen1, W Y Zhang2
1Ames Laboratory-US Department of Energy, Ames, Iowa 50011, USA and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Physical Review Letters
|March 4, 2014
Summary
Predicting crystal structures of novel nanoscale materials is now possible with advanced algorithms. This aids in developing high-performance permanent magnets without rare-earth elements, solving puzzles in complex intermetallic compounds.
Area of Science:
- Materials Science
- Crystallography
- Computational Materials Science
Background:
- Solving crystal structures of novel nanoscale phases is challenging due to disorder and competing polymorphs.
- Rapid quenching techniques often result in complex materials with nanoscale grains.
Purpose of the Study:
- To present a novel computational approach for predicting crystal structures of unknown phases without prior assumptions.
- To apply this method to solve complex crystal structures of Zr2Co11 polymorphs.
- To identify the hard magnetic phase and understand the origin of high coercivity in Zr2Co11.
Main Methods:
- Utilizing advances in computer speed and sophisticated algorithms for ab initio structure prediction.
- Employing a method that does not assume Bravais lattice type, atom basis, or unit cell dimensions.
- Applying the approach to analyze the orthorhombic, rhombohedral, and hexagonal polymorphs of Zr2Co11.
Main Results:
- Successfully predicted and solved the complex crystal structures of Zr2Co11 polymorphs.
- Identified the specific hard magnetic phase responsible for high coercivity.
- Provided insights into the origin of high coercivity in this intermetallic compound.
Conclusions:
- The developed computational approach is effective for exploring complex materials with nanoscale grains.
- This work resolves a long-standing puzzle regarding the crystal structures of Zr2Co11.
- The findings guide the development of high-performance permanent magnets without rare-earth elements.
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