Chemical synthesis, structure and magnetic properties of Co nanorods decorated with Fe3O4 nanoparticles

Magnetic anisotropic nanocomposites have attracted tremendous interests, due to their unexpected properties originating from the interactions of the interfaces except for the intrinsic features. In this work, we develop a facile solution chemistry synthesis method to prepare the one-dimensional (1D) Co-Fe3O4 heterostructures with hard magnetic property. Interestingly, the Fe precursor firstly decompose and nucleate individually, and then grow on the surface of the hexagonal closed-packed (hcp) Co nanorods (NRs) upon prolonging heating time at higher temperature, which is different from the general seed-mediated growth model. The distribution density of Fe3O4 nanoparticles (NPs) on the surface of the Co NRs can be varied with the addition of Fe source, modulating the values of coercivity and saturation magnetization for the Co-Fe3O4 heterostructures. The as-synthesized Co-Fe3O4 heterostructures maintain the hard magnetic properties with a coercivity value more than 2.5 kOe as well as a saturation magnetization value up to 128.3 emu g(-1), indicating the preservation of the anisotropy of the hcp Co NRs.