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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Strategy to control magnetic coercivity by elucidating crystallization pathway-dependent microstructural evolution of
Bum Chul Park1,2, Jiung Cho3, Myeong Soo Kim4
1Department of Materials Science and Engineering, Korea University, Seoul, 02481, Korea.
Nature Communications
|January 17, 2020
Summary
Researchers developed a unified model for mesocrystal formation, revealing two distinct crystallization pathways. This understanding allows precise control over magnetite mesocrystal size and magnetic properties.
Area of Science:
- Materials Science
- Crystallography
- Nanotechnology
Background:
- Mesocrystals, assemblies of crystallites, exhibit unique collective functionalities due to nonclassical crystallization.
- Precise control over mesocrystal size and microstructure is crucial for tuning their functions.
- The evolution of microstructure during mesocrystal formation via different pathways remains poorly understood.
Purpose of the Study:
- To propose a unified model for mesocrystal crystallization mechanisms.
- To elucidate the role of intermediate ferric (oxyhydr)oxide polymorphs in magnetite mesocrystal formation.
- To establish a method for independent control of mesocrystal diameter and crystallite size.
Main Methods:
- Observation of two distinct crystallization pathways for magnetite mesocrystals.
- Identification of different ferric (oxyhydr)oxide polymorphs as intermediates.
- Correlation of crystallization pathways with microstructure evolution.
- Magnetic coercivity measurements to assess microstructure control.
Main Results:
- A unified model explaining mesocrystal formation through two pathways involving ferric (oxyhydr)oxide intermediates.
- Demonstration of independent control over mesocrystal diameter and crystallite size.
- Establishment of a universal crystallite size effect on the magnetic coercivity of mesocrystals.
Conclusions:
- The proposed model provides a general approach to control mesocrystal microstructure by selecting crystallization pathways.
- This strategy enables effective control of magnetic coercivity in magnetite mesocrystal systems.
- Understanding crystallization mechanisms is key to harnessing the collective functionalities of mesocrystals.
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