Open AccessMagnetic susceptibility of ferrofluids determined from diffusion coefficient of a tracer
Author(s) -
Martı́n Hernández,
Ricardo Peredo-Ortiz
Publication year - 2022
Publication title -
revista mexicana de física/revista mexicana de física
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.181
H-Index - 25
eISSN - 2683-2224
pISSN - 0035-001X
DOI - 10.31349/revmexfis.68.031003
Subject(s) - ferrofluid , magnetic susceptibility , diffusion , isotropy , relaxation (psychology) , materials science , tracer , magnetization , volume fraction , thermal diffusivity , particle (ecology) , condensed matter physics , superparamagnetism , magnetic nanoparticles , colloid , nuclear magnetic resonance , thermodynamics , physics , chemistry , magnetic field , nanoparticle , nanotechnology , optics , psychology , social psychology , oceanography , quantum mechanics , geology , nuclear physics
Linear response methods allow studying magnetic susceptibility relaxation in isotropic colloidal magnetic fluids. We show a relationship between the susceptibility of macroscopic magnetization at thermal equilibrium and the diffusion constant of a tracer particle. The comparison of the predicted frequency-dependent susceptibility with computer simulations shows their agreement. Besides, at a low concentration of particles, it has the expected Debye behavior. However, the initial susceptibility yields only the qualitative trends of the existing experiments at a low volume fraction of particles and its temperature dependence.