ELECTROMAGNETIC PROPERTIES AND APPLICATION TO MICRO-EMC OF THE METAL-OXIDE COMPOSITE FILMS WITH A FIBER LIKE NANO-STRUCTURE

为了提高工业适用性和生产效率，对共蒸发法制备颗粒薄膜进行了研究。阐明了蒸发沉积的几个优点，并证实了蒸发沉积在高频下的性能得到了改善。主要研究内容如下：1.Ni80Fe20-(CaF2，SRF2，MgF2，b203)磁各向异性的制备和研究。2.纤维结构的磁化过程。3.如何控制相分离和渗透率。4.与纤维结构相关的TMR。5.高频渗透性。6.对薄膜作为EMC材料的评价。我们在研究中得到的结果是：(1)纤维结构根据相分离程度的不同而产生垂直各向异性或面内各向异性。(2)所有样品的TMR都很差，表明纤维结构仍处于不完全的相分离状态。(3)薄膜具有良好的磁导率频率分布。有些样品，如Ni8OFe20-(CaF2，B203)，其电阻率比通常的颗粒膜高两个数量级。(4)通过蒸发可以在较低的衬底温度下获得很高的沉积速率(比溅射高3个数量级)。(5)与100微米厚的传统噪声抑制片相比，厚度为2微米的薄膜对电磁传导噪声和辐射噪声的抑制和吸收性能几乎相同。总之，蒸发工艺在各种高频应用的颗粒材料的商业化生产中是有前途的。

Studies were made on granular thin films fabricated by co-evaporation instead of sputtering in order to improve industrious applicability and production efficiency. A few advantages of evaporative deposition were clarified and an improved performance at high frequencies was confirmed in this study. The subjects studied are :1.Fabrication and search of magnetic anisotropy in Ni80Fe20-(CaF2, SrF2, MgF2, B203). 2.Magnetization process of the fiber structure. 3.How to control phase separation and permeability. 4.TMR associated with the fiber structure. 5.Permeability at high frequencies. 6.Evaluation of the films as EMC materials.The results we have attained in the study are :(1)The fiber structure gives rise to either perpendicular anisotropy or inplane anisotropy depending on the degree of phase separation. (2)Poor TMR is observed for all the samples suggesting that the fiber structure is still in an imperfect phase separation state. (3)The films exhibit good frequency profiles of permeability. Some of the samples such as Ni8OFe20-(CaF2, B203) have resistivity higher than that of usual granular films by two orders. (4)Very high deposition rate (3 orders higher than sputtering) with lower substrate temperature is possible by evaporation. (5)The films with thickness of 2 microns exhibit almost the same performance in suppression and absorption of electromagnetic conductive noise and radiation noise in comparison with 100 micron thick conventional noise suppression sheets.In summary the evaporation process is promising in commercial production of granular materials for various kinds of high frequency applications.