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Time-dependent clustering and magnetization in magnetic colloidal suspensions.
Luis R Pérez-Marcos1, Ronal A DeLaCruz-Araujo2,3, Heberth Diestra-Cruz4
1Graduate School, Master Program in Mathematical Engineering, National University of Trujillo, Trujillo, La Libertad, Peru.
Soft Matter
|August 29, 2025
Summary
The clustering aggregation process influences magnetic colloidal suspension magnetization. Higher volume fraction and magnetic field interactions enhance magnetization by promoting side-by-side chain coupling.
Area of Science:
- Colloid and Surface Chemistry
- Magnetohydrodynamics
- Computational Physics
Background:
- Magnetic colloidal suspensions exhibit complex behavior influenced by particle interactions and external fields.
- Understanding the relationship between microstructural properties and macroscopic magnetization is crucial for applications.
Purpose of the Study:
- To analyze the influence of time-dependent clustering aggregation on the transient and equilibrium magnetization of magnetic colloidal suspensions.
- To investigate how microstructural properties, governed by volume fraction, dipolar coupling, and magnetic field strength, affect magnetization dynamics.
Main Methods:
- Brownian dynamics simulations were employed to model the magnetic colloidal suspension.
- Microstructural properties (nucleation-growth factor, mean cluster size, kinetic exponent, radial distribution function) were analyzed.
- Magnetization in transient and equilibrium regimes was studied in relation to microstructural characteristics and system parameters (volume fraction, dipolar coupling parameter, Langevin parameter).
Main Results:
- Higher dipolar coupling (λ) and volume fraction (ϕ) values reduce dipolar chain growth in the range 1 < α < 10 due to lateral chain interactions.
- These lateral interactions promote side-by-side coupling of dipolar chains, enhancing both transient and equilibrium magnetization.
- Significant discrepancies were observed between simulated equilibrium magnetization and existing predictive models for 0.01 ≤ α ≤ 10.
Conclusions:
- The study highlights the critical role of clustering aggregation and inter-chain interactions in determining the magnetization of colloidal suspensions.
- Langevin magnetic susceptibility (χL) can characterize dilute suspensions with strong magnetic interparticle interactions (χL ≥ 0.09).
- Findings suggest the need for refined models to accurately predict magnetization in these complex magnetic systems.
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