Magnetic Properties And High-Frequency Characteristics Of Fecoalo Gradient Composition Thin Films

5 x 25mm FeCoAlO gradient composition thin film was prepared with composite target by using RF magnetron sputtering. The Al-O composition gradient along the length direction of the film was introduced by Al2O3 chips asymmetrically arrayed on a Fe70Co30 target disk. The film was divided into five equal segments. All samples showed a low coercive force H-c of 4 - 8 Oe. The saturation magnetization 4 pi M-s increased continuously from 17.3 kGs for sample 1 (has more Al-O content) to 19.7 kGs for sample 5 and it was consistent with the increasing of Fe-Co composition. Meanwhile, these samples showed different anisotropy behaviors relating with Al-O composition. The sample 1 exhibited the same magnetization curve along the directions of G(parallel to) and G(perpendicular to) (G(parallel to) and G(perpendicular to) are parallel and perpendicular to the direction of the Al-O composition gradient, respectively). In both of G(parallel to) & G(perpendicular to) directions, the sample 1 showed a resonance frequency (f(r)) of around 2.6 - 3.0 GHz, while, in G(parallel to) direction, it showed a high value of real permeability mu'. The sample 5 exhibited a distinct in-plane uniaxial anisotropy and a good high-frequency response of 3.0 GHz resonance frequency. So these films having gradient composition exhibit are suggested for the use in integrated magnetic devices working in the GHz frequency range. (C) 2012 American Institute of Physics. [doi:10.1063/1.3677655]