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Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
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Anisotropic magnetic particles in a magnetic field
Ilya Martchenko1, Jérôme J Crassous2, Adriana M Mihut2
1Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden. jerome.crassous@fkem1.lu.se peter.schurtenberger@fkem1.lu.se and Adolphe Merkle Institute and Fribourg Center for Nanomaterials, University of Fribourg, Fribourg, Switzerland.
Soft Matter
|October 11, 2016
Summary
Magnetic ellipsoidal hematite colloids exhibit distinct phases based on packing and magnetic fields. Arrested dense packing leads to a switch from superparamagnetic to weakly ferromagnetic behavior, enabling remanent magnetization.
Area of Science:
- Colloid science
- Materials science
- Condensed matter physics
Background:
- Understanding the phase behavior and magnetic properties of colloidal suspensions is crucial for developing novel materials.
- Hematite colloids, with their magnetic properties, offer a unique platform for studying collective phenomena.
- The interplay between particle shape, packing fraction, and external magnetic fields dictates the emergent properties of these systems.
Purpose of the Study:
- To characterize the structural properties of magnetic ellipsoidal hematite colloids.
- To map the phase diagram as a function of packing fraction and magnetic field strength.
- To investigate the coupling between orientational order and bulk magnetic behavior.
Main Methods:
- Small-angle X-ray scattering (SAXS) for structural characterization.
- Computer simulations to model particle interactions and phase transitions.
- Analysis of magnetic field effects on colloidal assembly.
Main Results:
- Distinct isotropic, polarized non-nematic, and nematic phases were identified and mapped.
- Quantitative criteria for phase and arrest transitions were established.
- A transition from superparamagnetic to weakly ferromagnetic behavior was observed upon rotational arrest at a packing fraction of approximately 0.59.
Conclusions:
- Dense, arrested magnetic ellipsoidal colloids can exhibit persisting remanent magnetization.
- The study extends the colloid-atom analogy to include magnetic spin behavior.
- This work provides insights into designing magnetic colloidal systems with tunable properties.
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