Abstract: A series of multilayers of CoFeB-SiO₂ was fabricated by using DC/RF magnetron sputtering, and then annealed in vacuum at different temperatures. The results show that microstructures and electromagnetic properties of the CoFeB-SiO₂ multilayer films can be altered by varying the volume fraction of SiO₂ and the annealing temperature. High permeability along with high magnetic loss in the GHz frequency range is achieved in the optimized discontinuous multilayer films. Both real and imaginary part of the complex permeability are larger than 260 at 1.5GHz for these films, and the resistivity is as high as 1.38mΩ·cm. The CoFeB-SiO₂ multilayers are supposed to serve as the microwave absorbers in GHz range.

Key words: CoFeB-SiO₂, discontinuous multilayer, microwave electromagnetic, complex permeability