Regulation of saturation magnetization of magnetite by doping with group III elements

Magnetic Fe3O4 nanoparticles show promising applications in nanomedicine. However, the saturation magnetization (MS) of Fe3O4 nanoparticles synthesized in laboratory is usually not high enough, which greatly limits their application in drug delivery and magnetic hyperthermia. Here, by accurate hybrid density functional computation, the doping behavior of group III elements (including Al, Ga, and In) and the effects on magnetic and electronic properties are well studied. The results show that the doping behavior depends on the concentration of dopants. Interestingly, appropriate Ga and In doping concentrations can significantly increase the MS of Fe3O4. In addition, the doping of group III elements (Al, Ga and In) into Fe3O4 would not induce any defect states in the band gap but slightly increases the band gap. Our results provide a simple and feasible scheme for increasing the MS of magnetite, which is significant for the applications of Fe3O4 nanoparticles in drug delivery and magnetic hyperthermia. The doping behavior of group III elements (Al, Ga, and In) depends on the concentration of dopants. Appropriate Ga and In doping concentrations can significantly increase the MS of Fe3O4.