Compositional dependence of magnetic and high frequency properties of nanogranular CoFe-Yttrium-doped Zirconia films

摘要

Soft magnetic nanogranular CoFe-Yttrium-doped Zirconia (CoFe-YSZ) thin films were prepared by co-sputtering YSZ with different compositions of CoFe. By simply adjusting the ingredients of films, full-width at half-maximum of the imaginary permeability spectra of CoFe-YSZ films changed greatly. Based on this phenomenon, nanogranular CoFe-YSZ films with various compositions were deposited. And the characteristics of the electromagnetic noise suppression have been evaluated using an integrated coplanar waveguide (CPW) transmission line. A saturation magnetization (4 pi M-s) as high as 21 kGs, a ferromagnetic resonance (FMR) frequency above 3.5 GHz, a suitable value of 589 mu Omega cm, and a low coercivity of 7.39 Oe were obtained simultaneously when the volume fraction of CoFe was 0.73. The CoFe-YSZ film with x - 0.73 shows a very wide resonance peak with the full-width at half-maximum of 1 GHz. The absorption attenuation amplitude reaches to -8.1 dB at the resonance frequency f(r) = 3.5 GHz. In addition, the transmission signal attenuation decreases sharply at the resonance frequency and almost keeps constant when the frequency is lower than 1.2 GHz. It means the input transmission signal will pass through the signal line with tiny signal attenuation below its resonance frequency. (C) 2015 Elsevier B.V. All rights reserved.