Novel Hybrid Au/Fe3O4 Magnetic Octahedron-like Nanoparticles with Tunable Size

Octahedron-like Au/Fe3O4 magnetic nanoparticles are synthesized using decomposition of FeO(OH) and HAuCl4 with the presence of oleic acid in 1-octadecene solvent. In the octahedron-like hybrid particles, Fe3O4 mainly displayed the octahedral morphology and spherical Au nanoparticles partially embedded into one side of Fe3O4 octahedron. The size of particle could be tuned from 25 to 240 nm for the whole particle (mainly for Fe3O4) and 10 to 40 nm for Au by changing the proportion of the starting materials. The hybrid particles showed the magnetic properties of Fe3O4 with dependence on the size of Fe3O4 octahedron composite and the proportion of Fe3O4 to Au. Coercivity is observed in the hybrid Au/Fe3O4 octahedron-like nanoparticles (55 Oe for 25 nm, 135 Oe for 100 nm, and 159 Oe for 240 nm) at room temperature. These size-controllable hybrid Au/Fe3O4 magnetic octahedron-like particles, inheriting the advantages of Au and Fe3O4 nanoparticles, may evolve as useful building blocks for nano-and micro-electronic applications.