CoFeB/MgO不连续多层纳米软磁薄膜微波电磁特性

采用直流/射频磁控溅射方法和不连续多层交替沉积工艺，制备了CoFeB/MgO系列纳米不连续多层薄膜，研究了微波频段下的电磁性能.结果表明，通过调整CoFeB合金相和MgO介质相的相对含量可有效调控薄膜的微结构和电磁性能，且在［Co₆₄Fe₂₄B₁₂(0.7nm)/MgO(0.4nm)］₄₀薄膜中获得了优良的微波软磁性能和高电阻率，其饱和磁化强度1.3 T，难轴矫顽力130 A/m，电阻率3.4mΩ·cm，且共振频率高达2.1 GHz，磁导率实部μ′和虚部μ″在1.59 GHz处均高于240，并且在0.9—2 GHz宽频带范围同时大于100.该薄膜可用于微波吸收材料和电磁兼容的设计中. 关键词： 纳米磁性颗粒膜 磁导率频谱 电磁性能 吸波材料

Electromagnetic and microwave properties of discontinuous CoFeB/MgO soft magnetic multilayer films

A series of discontinuous multilayers of CoFeB-MgO was fabricated by using DC/RF magnetron sputtering, and the electromagnetic and microwave properties were investigated. The results show that the microstructure and electromagnetic properties of the CoFeB-MgO discontinuous multilayer films can be altered by varying the relative content of the magnetic CoFeB phase and the insulating MgO phase. High performance microwave soft magnetic properties along with high resistivity are achieved in the discontinuous ［Co₆₄Fe₂₄B₁₂(0.7nm)/MgO(0.4nm)］₄₀ multilayer film. This film has the saturation magnetization of 1.3 T, hard axis coercivity of 130 A/m, and resistivity of 3.4 mΩ·cm. Moreover, the resonance frequency is about 2.1 GHz for this film. Both the real part μ′ and the imaginary part μ″ of the measured permeability are larger than 240 at 1.59 GHz and are both larger than 100 from 0.9 GHz to 2 GHz. So this film has potential for serving as the microwave absorbers and electromagnetic compatibility materials in the GHz frequency range.