2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/100542We have studied the magnetic behavior of dextran-coated magnetite (Fe$_3$O$_4$) nanoparticles with median particle size $\left<d\right>=8$ $nm$. Magnetization curves and in-field Mössbauer spectroscopy measurements showed that the magnetic moment $M_S$ of the particles was much smaller than the bulk material. However, we found no evidence of magnetic irreversibility or non-saturating behavior at high fields, usually associated to spin canting. The values of magnetic anisotropy $K_{eff}$ from different techniques indicate that surface or shape contributions are negligible. It is proposed that these particles have bulk-like ferrimagnetic structure with ordered A and B sublattices, but nearly compensated magnetic moments. The dependence of the blocking temperature with frequency and applied fields, $T_B(H,ω)$, suggests that the observed non-monotonic behavior is governed by the strength of interparticle interactions.11 pages, 7 figures, 3 TablesMaterials Sciencetext