Adjusting the magnetic properties of Ni0.5Zn0.5Fe2O4 thin film for high frequency applications by introducing Fe65Co35 alloy nanoclusters

Recently, duo to the growing pursuits for miniaturization and steadily increasing operating frequency into the gigahertz (GHz) range of electromagnetic devices, materials with high resistivity, high saturation magnetization and high resonance frequency have become consuming all-important. The soft magnetic ferrite thin films, such as NiZn ferrite thin films which have high resistivity, are supposed to be a promising material for high frequency applications [1, 2]. However, these ferrite thin films cannot keep high permeability in the GHz frequency range due to their low saturation magnetization. Therefore, much effort has been focused into improving their magnetic properties. It is considered that “nanocomposite systems” play an important role in optimizing the magnetic properties of NiZn ferrite [3-4]. However, it is difficult to prepare the above-mentioned nanocluster-matrix dualistic magnetic nanocomposite film by traditional magnetron co-sputtering deposition method. For example, when NiZn ferrite target and a Fe-Co alloy target are used to prepare a composite film via a co-sputtering process, Fe and Co atoms sputtered from alloy target and Fe, Ni, Zn atoms sputtered from NiZn ferrite target tend to form a new type of ferrite film whose composition will be different from that of original NiZn ferrite target rather than forming the designed nanocluster-matrix dualistic magnetic nanocomposite film.