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Machine-learning-guided optimization of cobalt doping in Sm(Fe,Ti,V)12-based magnets
Toni Subagja1,2, Nikita Kulesh1, Jiasheng Zhang1
1Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan.
Science and Technology of Advanced Materials
|July 10, 2026
Summary
Optimizing titanium (Ti) and vanadium (V) ratios in samarium-iron-cobalt (Sm(Fe,Co)12) magnets improves coercivity. Ti-rich compositions suppress coercivity loss, balancing magnetization for practical applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Magnetism
Background:
- Cobalt (Co) substitution in samarium-iron (SmFe12) compounds enhances saturation magnetization.
- This substitution often leads to significant coercivity degradation, limiting practical applications.
- Machine learning (ML) offers a data-driven approach to optimize material compositions and mitigate these issues.
Purpose of the Study:
- To investigate the effect of Ti/V stabilizer ratio on coercivity in Co-doped SmFe12-based compounds.
- To identify optimal compositions that suppress coercivity degradation while maintaining enhanced magnetization.
- To validate ML predictions through experimental synthesis and characterization.
Main Methods:
- Compiled a dataset from published and in-house experimental data on Sm(Fe,Co)12 compounds.
- Applied machine learning techniques to predict optimal compositions for coercivity retention.
- Synthesized Ti-rich and Ti-lean SmFe12-based ribbons via rapid solidification and characterized their microstructure and magnetic properties.
Main Results:
- ML predictions indicated suppressed coercivity degradation for Ti/V ratios exceeding ~1.0.
- Experimentally, Ti-rich ribbons showed improved resistance to coercivity degradation compared to Ti-lean ribbons.
- Co-doping led to secondary SmFe2 phases and increased twinned grains, contributing to coercivity reduction, while Ti-rich alloys maintained a better anisotropy field.
Conclusions:
- Maintaining a Ti-rich stabilizer composition is crucial for mitigating coercivity loss in Co-doped SmFe12 magnets.
- Optimizing the matrix composition enables a balance between high coercivity and saturation magnetization.
- This strategy advances the development of SmFe12-based permanent magnets for practical applications.
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