Trial Production of the High Frequency Permeance meter

磁记录技术的趋势是越来越高的记录密度和更高的数据速率。然后，要求读写头的磁性薄膜在更高的频率区域表现出高磁导率。在本项目中，研究了在1 GHz以下的超高频范围内测量软磁薄膜的高频磁导率。通过使用射频阻抗仪(YHP419A)测量软磁薄膜插入线圈或带状线前后阻抗的变化来估算磁性薄膜的有效磁导率。综合考虑测量电路的谐振频率和阻抗测量仪的灵敏度，根据测量频率的不同，在不同电抗的线圈和带状线中选择合适的线圈和带状线。利用等效电路确定了磁导率的实部和虚部。通过使用一条短的带状线，可以很容易地测量高达1 GHz的磁导率。结果表明，CoZr/SiO_2多层膜的频率响应得到改善，低频损耗明显降低。在非常薄的薄膜中，进一步发现频率响应变得比较厚的和多层膜好得多。实部和虚部以大约从基特尔方程计算出的共振频率相交。

The magnetic recording technology trend is towards increasingly higher recording density and higher data rates. Then magnetic thin films for read-write heads are required to exhibit a high permeability in still higher frequency region. In this project, the measurement of the high frequency permeability of soft magnetic thin film was investigated in ultra high frequency range up to 1GHz.The effective permeability of magnetic films were estimated from the change of impedance before and after inserting the film into a coil or strip line using a rf impedance meter (YHP419A). Considering the resonance frequency of the measurement circuit as well as the sensitivity of the impedance meter, among various coils and strip lines with different reactance, suitable ones were chosen depending on the frequency of the measurement. The real and imaginary parts of permeability were determined using the equivalent circuit. By using a short strip line, it became easy to measure the permeability up to 1GHz. As a result, it was found that the frequency response was improved in CoZr/SiO_2 multilayr and loss part at low frequency was much deduced in the multilayr. In the very thin film, the frequency response was further found to become much better than thicker and multilayr films. The real and imaginary parts cross with each other at about the resonance frequency calculated from Kittel's equation.