Dynamo magnetic domain analysis by nano-scale resolution MFM for high-density magnetic recording media

为了发展超过1T比特/英寸的超高密度磁记录介质，降低介质磁化强度的时空起伏引起的介质噪声是一个重要的问题。因此，需要对磁畴结构进行高空间分辨率的动态分析。本研究利用强磁场下的原位磁力显微镜(MFM)进行了以下研究：(1)研制了横向分辨率小于5 nm的MFM系统；(2)发展了利用MFM对磁畴结构进行动态分析的方法；(3)将其应用于高密度磁记录介质中，获得了以下结果：1)利用L1_0有序FePT合金制备了分辨率为10 nm的高矫顽力MFM尖端(Hc&Gt；10kOe)。通过对不同形状的针尖传递函数的计算，阐明了分辨率小于5 nm的高分辨率针尖的设计。椭圆度为~tan70°的球形圆柱形尖端是高分辨率MFM尖端较好的候选材料。2)发展了强磁场下的原位动态MFM测量，并将其应用于各种高密度磁记录介质，如合成蕨类磁性介质、图案化介质。揭示了纳米碳氢化合物在介质中的分布。

To develop ultra-high density magnetic recording media more than 1Tbit/inch^2 the reduction of media noise, which was occurred by the spatial and temporal fluctuation of media magnetization is important problem. Therefore the dynamic analysis of magnetic domain structure with high spatial resolution will be needed. In the present study, the research was carried out by using in-situ magnetic force microscope (MFM) in strong magnetic fields for the following purpose.(1)the development of MFM system with lateral resolution less than 5 nm(2)the development of dynamic analysis of magnetic domain structure using MFM(3)application of to high density magnetic recording mediaThe following results are obtained.1)High coercivity MFM tips with 10nm resolution (Hc>10kOe) were fabricated by using L1_0 ordered FePt alloy. The design of high-resolution tips with less than 5nm resolution were clarified by calculating the transfer function of the tips with various shape. Cylindrical tips with an spheroidal tip-end having an ellipticity of〜tan70°was found to be better candidates of high resolution MFM tips. The fabrication of these tips is in progress.2)In-situ dynamic MFM measurements in strong magnetic field were developed and applied to various high-density magnetic recording media, such as synthetic fern-magnetic media, patterned media. The nano-scale Hc distribution in the media was revealed.