2017/08/16 by Kunlun Bai, Bai, Kunlun, Aparna Nair-Kanneganti +9
Biochemistry, Genetics and Molecular Biology · Engineering · #Characterization and Applications of Magnetic Nanoparticles #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Magnetic and Electromagnetic Effects #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.1708.05051
openalex publication_date 2017/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We characterize how suspensions of magnetic particles in a liquid respond to a magnetic field in terms of the effective magnetic susceptibility χeff using inductance measurements. We test a model that predicts how χeff varies due to demagnetization, as a function of sample aspect ratio, particle packing fraction, and particle aspect ratio. For spherical particles or cylindrical particles aligned with external magnetic field, the model can be fitted to the measured data with agreement within 17%. However, we find that the random alignment of particles relative to the magnetic field plays a role, reducing χeff by a factor of 3 in some cases, which is not accounted for in models yet. While suspensions are predicted to have χeff that approach the particle material susceptibility in the limit of large particle aspect ratio, instead we find a much smaller particle aspect ratio where χeff is maximized. A prediction that χeff approaches the bulk material susceptibility in the limit of the packing fraction of the liquid-solid transition also fails. We find χeff no larger than about 4 for suspensions of iron particles.