Magnetic interactions between nanoscale domains in liquids

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Interactions between nanoscale particles in liquids are influenced by external magnetic fields (eMFs).
• The precise effects of eMFs on these interactions are not well understood.
• Nanoparticles often contain localized magnetic domains.

Purpose of the Study:

• To model and investigate the effective interactions between localized magnetic nanoparticles (LMNPs) in a solvent under external magnetic fields.
• To understand how magnetic nanodomains influence nanoparticle interactions compared to individual ions.

Main Methods:

• A simplified model of solvated nanoparticles with surface magnetic nanodomains was developed.
• Classical density functional theory was employed to calculate effective interactions.
• Interactions were analyzed considering electrostatic, van der Waals, hydration, and magnetic dipole forces.

Main Results:

• Magnetic dipole interactions of nanodomains can compete with other forces like van der Waals and hydration.
• External magnetic fields significantly alter LMNP interactions, making them more attractive or repulsive at short distances (<1 nm).
• Solvent correlations cause oscillatory behaviors in LMNP interactions, unaffected by eMFs.

Conclusions:

• External magnetic fields play a critical role in the aggregation of nanoparticles with magnetic nanodomains.
• The model demonstrates that nanodomain magnetic moments are key drivers of eMF-influenced interactions.
• Understanding these eMF-driven interactions is crucial for controlling nanoparticle assembly and behavior.