Small-angle neutron scattering with polarization analysis reveals that Fe₃O₄ nanoparticles with 90 Å diameters have ferrimagnetic moments significantly reduced from that of bulk Fe₃O₄ at 10 K, nominal saturation. Combined with previous results for an equivalent applied field at 200 K, a core-disordered shell picture of a spatially reduced ferrimagnetic core emerges, even well below the bulk blocking temperature. Zero-field cooling suggests that this magnetic morphology may be intrinsic to the nanoparticle, rather than field induced, at 10 K.