【作者】 杨啸林； 葛世慧； 阮成礼；

【Author】 YANG Xiao-lin, GE Shi-hui, RUAN Cheng-li ( College of Physics and Electronic Science, University of Electronic Science and Technology of China, Chengdu 610054, China; Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000, China)

【机构】 电子科技大学物理电子学院； 兰州大学教育部磁学与磁性材料重点实验室；

【摘要】 利用磁控溅射法制备了系列Fe65Co35-SiO2纳米颗粒膜材料。XRD谱和TEM明场像显示bcc结构的 Fe65Co35纳米金属颗粒均匀的镶嵌在SiO2绝缘介质中, 并且颗粒粒径有较宽的分布。在体积分数x为0．5-0．7 的范围内,其矫顽力Hc最大不超过318．4A/m,而电阻率ρ最大达到5500μΩ·cm。特别是x=0．57的样品,Hc 为135．32A/m,而ρ达2860μΩ·cm,比纯金属的大3个量级,这使得该材料在用于微波吸收中更容易实现阻抗匹配。对x=0．57样品的磁谱测量显示磁导率的虚部μ”在频率f>700MHz时,随频率的增大而迅速增大,在 f=2．4GHz时μ”达到最大值,约180。并且在f达到 9GHz时,μ”仍有15左右．这表明该样品具有较宽的微波吸收带宽和高效的吸波能力。我们认为,磁性纳米颗粒膜的这种高效的吸波特性主要来源于s-d电子的交换耦合作用,即相邻颗粒的d电子通过s传导电子的关联作用而发生交换相互作用。更多还原

【Abstract】 Series of Fe65Co35-SiO2 nano-granular films were fabricated by magnetron co-sputtering. The study of XRD and TEM show that the films consist of Fe65Co35 magnetic metal particles uniformly embedded in the amorphous insulating SiO2 matrix and the particle distribution is relatively wide. With x changes from 0.7 to 0.5, the films exhibit small coecivity Hc not exceeding 318.4A/m and high electrical resistivity p up to 5480 μΩ·cm. The minimum Hc of 135.32A/m was obtained for the sample of x=0.57 whose resistivity is 2860μΩ·cm, 3 orders higher than that of pure metals, which makes the impedance matching easily. For the sample of x=0.57, at the frequency higher than 700MHz, the imaginary part μ" of complex permeability increases with increasing frequency, and reach the maximum value of 180 at 2.4GHz. Furthermore, at the frequency of 9GHz, μ" still remains 15. We consider this microwave absorbing properties for the nanogranular films are attributed to exchange coupling of s-d electrons, namely, the exchange interaction due to the d electrons of neighboring particles conjunction with s conduction electrons.更多还原