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Probing spin waves in Co3O4 nanoparticles for magnonics applications.
Mikhail Feygenson1,2,3, Zhongyuan Huang4, Yinguo Xiao4
1European Spallation Source ERIC, SE-221 00 Lund, Sweden. mikhail.feygenson@ess.eu.
Nanoscale
|December 22, 2023
Summary
Synthesizing cobalt oxide (Co3O4) nanoparticles of different shapes reveals how size and surface effects influence magnetic properties. Cubic nanoparticles show slightly enhanced exchange interactions compared to spherical ones, impacting future magnonic device design.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Controlling magnetic properties of spinel nanoparticles is achievable through precise synthesis of shape and size.
- Surface effects on static magnetic properties are understood, but their impact on spin wave dispersion remains under investigation.
- Manipulating spin waves via surface and defect engineering in magnetic nanoparticles is crucial for developing advanced magnonic devices.
Purpose of the Study:
- To investigate the influence of shape and size on the static and dynamic magnetic properties of cobalt oxide (Co3O4) nanoparticles.
- To compare the magnetic behavior of cubic and spherical Co3O4 nanoparticles with bulk references.
- To understand the role of surface effects on spin wave dispersion in magnetic nanoparticles.
Main Methods:
- Synthesis of cubic and spherical cobalt oxide (Co3O4) nanoparticles.
- Characterization of magnetic and crystal structures using various experimental techniques.
- Direct measurement of spin wave dispersions via inelastic neutron scattering.
Main Results:
- A subtle but significant increase in exchange interactions was observed in cubic Co3O4 nanoparticles compared to spherical ones and bulk powder.
- Spherical Co3O4 nanoparticles exhibited bulk-like exchange interactions, even with a ferromagnetic contribution from canted surface spins.
- Shape and size significantly affect the dynamic magnetic properties, specifically spin wave dispersion, in Co3O4 nanoparticles.
Conclusions:
- The shape of Co3O4 nanoparticles demonstrably influences their magnetic exchange interactions.
- Surface spin canting in spherical nanoparticles does not disrupt their overall bulk-like exchange properties.
- These findings provide critical insights for engineering magnetic nanoparticles for tailored magnonic device applications.
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