Abstract :
This letter reports the novel nanostructure and excellent magnetic properties of Co19.35Fe53.28Hf7.92O19.35 films with varying thicknesses. Among the samples investigated, the film with a thickness of 432 nm exhibits the most excellent magnetic properties: high saturation magnetization, 4 π M s ∼ 19.86 kG , low coercivity, H c ∼ 1.5 Oe , and high hard-axis anisotropy field of H k ∼ 84 Oe . The magnetic permeability remains almost stable up to 3 GHz and reaches a maximum at the ferromagnetic resonant frequency of 4.024 GHz. The excellent magnetic characteristics of this film in addition to a very high electrical resistivity of 3569 μΩ cm make it ideal for uses in high-frequency applications of micromagnetic devices. It reveals that these superior properties are ascribed to the formed peculiar nanostructure. A magnetic phase separation appears to occur strongly as the film thickness increases over 437 nm, which, in turn, modifies the high-frequency behavior.
