Magnetic resonance study of zero-field-frozen magnetite-based biocompatible magnetic fluid

In this paper, magnetic resonance was used to investigate biocompatible magnetic fluid samples based on dextran-coated magnetite nanoparticles (9.4-nm average diameter). Samples containing different particle concentration (4.8 × 10¹⁴ and 2.4 × 10¹⁶ particle/cm³) were investigated in the temperature range of 100-300 K. Analysis of the temperature dependence of the resonance linewidth (ΔH_R) revealed larger average particle diameter (about 13% larger) in the concentrated sample, indicating particle agglomeration. Larger particle diameter (about 17% larger) was also revealed from the analysis of the temperature dependence of the resonance field (H_R).