Study on the Development of Giant Magnetostrictive Materials for Applications of Dynamical Systems in Wide Frequency Range

在本研究中，确立了以下两个问题。这些结果是在以往关于提高超磁致伸缩材料（GMM）频率响应带宽和改善其动态特性的研究基础上得到的。(1)提高GMM的电阻可以改善频率响应。一种有用的替代方法是减小GMM的厚度或直径，理论上可以将响应提高2倍。本研究的主要成果是开发了一种独特的方法来同时满足这两种手段。采用一种制备自旋涂层磁带磁粉的技术实现了该方法。制备直径在10 ~ 30微米的GMM细粉是本研究的关键技术。GMM粉与高分子树脂的混合也显著提高了材料的电阻。因此，驱动频率范围已从以前的1kHz推到500khz。(2)采用机械工程与精密工程相结合的剪切方法对该方法进行了验证。也就是说，通过在硅片上利用传统的切割技术，实现了GMM薄层的制造。通过外部控制磁化强度，使结晶方向选择在<111>的最大磁致伸缩方向上。这种方法被称为改进布里奇曼方法。将用上述方法制备的GMM锭切成薄层，厚度为0.1 mm。结果表明，该系统具有优异的磁弹性能E=32000 J/m^3，响应稳定在1 MHz以内。新产品开发：如项目11所示，基于本研究已申请了两项专利。（一）超磁致伸缩振动传感器（二）超磁致伸缩泵

In this research, the following two issues have been established. These results were obtained on the basis of past research efforts regarding enhancement of the band width of the frequency response in giant magnetostrictive materials (GMM) and improvement on their dynamic characteristics.(1) Improvement of frequency response can be achieved by increase of electric resistance of GMM.A useful alternative to it is to decrease the thickness or the diameter of GMM,which theoretically enhances the response by the power of two.Main achievement of this study is that an unique method has been developed to satisfy the two means at the same time. This method was materialized by employing a technique by which magnetic powders of spin coating magnetic tapes are produced. This is a key technology in this study to fabricate fine powders of GMM whose diameter is in the range of 10 to 30 micrometers. Also mixing the GMM powders with high molecular resin significantly contributed increase of the electric resistance of the compound. As a result, the driving frequency range has been pushed from previous 1kHz to 500 kHz.(2) This method was substantiated by means of shear combination of mechanical engineering and precision engineering. That is, fabrication of thin layrs of GMM was attained by utilizing conventional dicing technology in Silicon wafers. Additional technology was incorporated by externally controlling magnetization so that the crystallization direction is chosen along <111> which is the largest magnetostriction direction. This method is called Modified Bridgman Method. Dicing a GMM ingot prepared in the aforementioned method yielded thin layrs of 0.1 mm in thickness. As a result, outstanding magneto elastic energy of E=32000 J/m^3 and stable response up to 1 MHz have been achieved.Development of novel products : as shown in Item 11, two patents have been filed based on this study.(i) Giant magnetostrictive vibration sensor(ii) Giant magnetostrictive pump