“…Especially, nanoparticles of iron oxide such as Fe 3 O 4 and γ -Fe 2 O 3 are reported to be applicable as a material for use in drug delivery systems (DDS), magnetic resonance imaging (MRI), and cancer therapy [5][6][7]. For such practical uses of magnetic nanoparticles, the particle size, magnetic properties, and surface properties of the nanoparticles are of great importance.…”