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Phase transformation-induced tetragonal FeCo nanostructures
Maogang Gong1, Alec Kirkeminde, Manfred Wuttig
1Department of Chemistry, University of Kansas , Lawrence, Kansas 66045, United States.
Researchers developed a new method to create high-performance tetragonal iron-cobalt (FeCo) nanomagnets without rare-earth elements. This technique uses phase transformation to control structure and enhance magnetic properties for potential green energy applications.
Area of Science:
- Materials Science
- Nanotechnology
- Magnetism
Background:
- Tetragonal FeCo nanostructures offer high magnetocrystalline anisotropy and magnetization without rare-earth elements.
- Controlling the metastable structure, size, and stoichiometry of these nanostructures is challenging.
Purpose of the Study:
- To demonstrate a novel templated growth and phase transformation method for fabricating high-performance tetragonal FeCo nanostructures.
- To investigate the influence of shell thickness and stoichiometry on magnetic properties.
Main Methods:
- AuCu templated FeCo shell growth.
- Thermally induced phase transformation of AuCu core (FCC to L10).
- Experimental characterization and lattice mismatch calculations to confirm structural changes and relaxation.
Main Results:
- Successfully triggered FeCo shell transformation from BCC to body-centered tetragonal phase.
- Achieved high coercivity (846 Oe) and saturation magnetization (221 emu/g) in the tetragonal FeCo structure.
- Identified a critical FeCo shell thickness for relaxation and confirmed shell thickness/stoichiometry dictate magnetic characteristics.
Conclusions:
- The study provides a general route to fabricate high-performance metastable nanomagnets using phase transformation.
- This method enables control over structure and magnetic properties of FeCo nanostructures.
- Potential applications in green energy technologies are highlighted.
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