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Superspin Glass Dynamics and Memory Effects in FeCo Nanoparticle Systems
Hur Abbas1, Tej Raj Karki1, Pramanand Joshi1
1Department of Physics, The University of Texas at Arlington, 502 Yates St., Arlington, Texas, 76019-9800, United States.
Nanotechnology
|August 3, 2026
Summary
Controlling the volume fraction of iron-cobalt (FeCo) nanoparticle assemblies stabilizes magnetic glassy dynamics. Low-volume fractions show superspin-glass behavior due to dipolar interactions, enabling new magnetic material designs.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Magnetic nanoparticle assemblies exhibit complex dynamics influenced by interparticle interactions.
- Controlling these interactions is key to stabilizing desired magnetic states for applications.
Purpose of the Study:
- To investigate the effect of volume fraction on magnetic dynamics in FeCo nanoparticle assemblies.
- To demonstrate the potential for engineering collective magnetic states through controlled assembly.
Main Methods:
- Fabrication of FeCo nanoparticle assemblies with varying low volume fractions.
- Characterization of magnetic properties, including aging, memory effects, and coercivity.
- Analysis of collective freezing phenomena mediated by dipolar interactions.
Main Results:
- Low-volume fraction FeCo nanoparticle assemblies display superspin-glass-like behavior.
- Evidence of characteristic aging and memory effects confirms collective freezing.
- Enhanced low-temperature coercivity suggests interaction-induced effective anisotropy.
Conclusions:
- Nanoparticle volume fraction is a scalable parameter for controlling collective magnetic states.
- This work provides a versatile strategy for designing nanoparticle-based magnetic materials with tunable dynamic responses.
