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Realizing high magnetic moments in fcc Fe nanoparticles through atomic structure stretch
S H Baker1, M Roy, S C Thornton
1Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK. bak@le.ac.uk
Summary
Altering the atomic structure of iron (Fe) nanoparticles by embedding them in a copper-gold matrix induces a switch from body-centered cubic (bcc) to face-centered cubic (fcc) structure. This structural change significantly enhances the magnetic moment of the Fe nanoparticles.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Iron (Fe) nanoparticles exhibit unique magnetic properties influenced by their atomic structure.
- Controlling the crystalline phase of nanoparticles is crucial for tuning their magnetic behavior.
- Embedding nanoparticles in specific matrices can alter their structural and magnetic characteristics.
Purpose of the Study:
- To investigate the structural transformation of Fe nanoparticles within a Cu(1-x)Au(x) matrix.
- To correlate changes in atomic structure with the resulting magnetic moment.
- To achieve a high magnetic moment state in Fe nanoparticles through structural control.
Main Methods:
- Co-deposition of Fe nanoparticles and Cu(1-x)Au(x) matrix using gas aggregation and MBE-type sources.
- Extended X-ray Absorption Fine Structure (EXAFS) measurements to analyze atomic structure and lattice expansion.
- Systematic variation of gold (Au) content in the Cu(1-x)Au(x) matrix.
Main Results:
- Fe nanoparticles transitioned from a bcc to an fcc structure upon embedding in the Cu(1-x)Au(x) matrix.
- Lattice expansion was observed in both the matrix and Fe nanoparticles with increasing Au content.
- A significant increase in the atomic magnetic moment of Fe nanoparticles was measured, reaching ~2.5 ± 0.3 μ(B)/atom.
- EXAFS data indicated a tetragonal stretch in the Fe nanoparticles.
Conclusions:
- Controlled modification of atomic structure is an effective route to enhance magnetic properties of Fe nanoparticles.
- The fcc phase in Fe nanoparticles, induced by the Cu(1-x)Au(x) matrix, leads to a high magnetic moment state.
- This study demonstrates a method for tuning nanoparticle magnetism through matrix engineering and structural phase control.
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