Simultaneous acquisition of Fe3O4 monocrystals: Tunable magnetic properties with various morphologies

Fe 3 O 4 nanoparticles (NPs) with a face-centered cubic (fcc) structure and two different morphologies (nanospheres and nanoprisms) were synthesized by a facile one-step method. The synthesized Fe 3 O 4 nanospheres and nanoprisms were monocrystalline and separable in a magnetic field. In different volume ratios of oleylamine (OAm) to dibenzyl ether, the sizes of the prepared Fe 3 O 4 NPs ranged from 5 to 21 nm. The OAm amount in the synthesis can significantly control the morphology of Fe 3 O 4 NPs. As the OAm content increased from 10 ml to 30 ml, the faceted nanoprisms shrank while the nanospheres enlarged. At an OAm content of 25 ml, the nanoprisms diminished while more hexagonal and sphere-like particles appeared, implying a critical point of morphology transition from triangle to hexagon. The magnetic properties also depended on the NP morphology and size. The prepared Fe 3 O 4 NPs are promising candidates in medical applications such as magnetic resonance imaging, targeted drug delivery, blood purification, and tumor hyperthermia.