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Size effect on the structural and magnetic phase transformations of iron nanoparticles
Alexis Front1,2,3, Georg Daniel Förster4, Chu Chun Fu5
1Université Paris-Saclay, ONERA, CNRS, Laboratoire d'Étude des Microstructures (LEM), 92322, Châtillon, France.
Nanoscale
|October 17, 2024
Summary
Surface effects enhance magnetism in iron nanoparticles (Fe NPs), increasing their Curie temperature as size decreases. This contrasts with solid-solid transitions, offering insights into Fe NP properties for applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Iron nanoparticles (Fe NPs) are vital low-dimensional materials.
- Their magnetic properties and allotropes vary with temperature.
- Understanding size-dependent transformations is crucial for applications.
Purpose of the Study:
- To characterize atomic-scale structural and magnetic transformations in Fe NPs.
- To investigate the influence of particle size on these transformations.
Main Methods:
- Development of a tight-binding model with a Stoner term for magnetism.
- Implementation in a Monte Carlo code for structural and magnetic relaxation.
- Atomic-scale simulation of Fe nanoparticle behavior.
Main Results:
- Surface effects significantly reinforce magnetism in Fe NPs.
- Curie temperature increases as nanoparticle size decreases.
- Solid-solid transition temperature shows an inverse relationship with size.
Conclusions:
- Fe NP magnetism is strongly influenced by surface reinforcement.
- Size-dependent magnetic and structural properties are elucidated.
- Findings are critical for advancing Fe NP applications.
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