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Updated: Mar 27, 2026
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Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
Published on: December 6, 2021
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Structure and magnetism in Cr-embedded Co nanoparticles
1Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK.
Summary
We studied cobalt nanoparticles within a chromium matrix, finding a core-shell structure. This structure causes reduced magnetism and exchange bias in the cobalt nanoparticles.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Nanocomposite films offer tunable magnetic and structural properties.
- Understanding nanoparticle-matrix interactions is crucial for advanced materials.
Purpose of the Study:
- To investigate the atomic structure and magnetism of cobalt nanoparticles embedded in a chromium matrix.
- To elucidate the core-shell structure and its influence on magnetic properties.
Main Methods:
- Co-deposition using gas aggregation and molecular beam epitaxy (MBE).
- Extended X-ray Absorption Fine Structure (EXAFS) for atomic structure analysis.
- Vibrating sample magnetometry (VSM) for magnetic property investigation.
Main Results:
- Cobalt nanoparticles adopt a body-centered cubic (bcc) structure, similar to the chromium matrix, with some disorder.
- Net cobalt magnetic moment per atom is significantly reduced compared to bulk cobalt, decreasing with lower cobalt concentration.
- All samples exhibited exchange bias after field cooling below 30 K, with the largest effect in the most dilute sample.
Conclusions:
- Structural and magnetic findings suggest interfacial alloying, forming a core-shell structure.
- The core consists of a reduced ferromagnetic cobalt core, surrounded by an antiferromagnetic cobalt-chromium alloy shell.
- This core-shell structure explains the observed reduced magnetism and exchange bias in the cobalt nanoparticles.
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