Cross-sectional magnetic domain analysis by three-dimensional magnetic charge distribution measurement in magnetic thin films

通过磁性薄膜中三维磁荷分布测量进行横截面磁畴分析

• 批准号: 12650048
• 负责人: SAITO Hitoshi
• 金额: $ 1.79万
• 依托单位: Faculty of Engineering and Resource Science, Akita University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650048/
• 关键词: magnetic force microscope; microscopic magnetic domain structure; magnetic recording media

In order to improve the recording density for recent high density magnetic recording media, the observation and control of magnetic domain structure for these films in not only the film plain direction but also the cross-sectional direction of films is strongly needed, because of the reduction of medium noise due to tlie fluctuation of magnetization. In the present study, the method of three-dimensional magnetic charge distribution measurement in magnetic thin films by using magnetic force microscope (MFM) was investigated. The following results are obtained.1) Three-dimensional magnetic chargedistribution measurement is possible in the case that the resolution of MFM is limited by the digitizing resolution of the input signals in MFM. This measurement can be done by subtracting the experimentally obtained MFM signals from the transformed MFM signals with same tip-sample distance to which are transformed from the signals measured at different tip-sample distance by MFM signal transformation method. This method is verified by computer simulation2) For three-dimensional magnetic charge distribution measurement, the MFM tip whose magnetic direction does not change by the stray field of MFM samples at short tip-sample distance is needed. We developed high coercivity MFM tips coated by sputtered L10 ordered CoPt films with Hc = 14kOe.3) For three-dimensional magnetic charge distribution measurement, it is important to know the MFM tip magnetization. Therefore we developed the method of in-situ magnetic hysteresis measurement of MFM tips by detecting the alternating force of MFM tips with applying alternating magnetic field to MFM tips.4) The improvement of MFM resolution is effective for three-dimensional magnetic charge distribution measurement. We developed the high-resolution MFM with 10 nm resolution by increasing the dynamic range of MFM input signals and using Lock-in amplifier to reduce signal noise.

为了提高近年来高密度磁记录介质的记录密度，强烈需要对这些薄膜的磁畴结构不仅在薄膜平面方向上而且在薄膜的横截面方向上进行观察和控制，因为磁化强度波动会降低介质噪声。本研究研究了利用磁力显微镜（MFM）测量磁性薄膜三维磁荷分布的方法。得到如下结果： 1)在MFM分辨率受到MFM输入信号数字化分辨率限制的情况下，可以实现三维磁荷分布测量。该测量可以通过从具有相同尖端-样品距离的变换MFM信号中减去实验获得的MFM信号来完成，该变换信号是通过MFM信号变换方法从不同尖端-样品距离处测量的信号变换得到的。该方法通过计算机仿真得到验证。2)对于三维磁荷分布测量，需要在短尖头-样品距离下，其磁力方向不会因MFM样品的杂散场而改变。我们开发了高矫顽力MFM尖端，其表面涂有溅射的L10有序CoPt薄膜，Hc = 14kOe。3）对于三维磁荷分布测量，了解MFM尖端磁化强度非常重要。因此我们提出了通过对MFM尖端施加交变磁场来检测MFM尖端的交变力来原位测量MFM尖端磁滞的方法。4）MFM分辨率的提高对于三维磁荷分布测量是有效的。我们通过增加 MFM 输入信号的动态范围并使用锁定放大器来降低信号噪声，开发了分辨率为 10 nm 的高分辨率 MFM。

项目成果

S.Asakura, S.Ishio, A.Okada, H.Saito: "Magnetic Domain Percolation of Co_x(SiO_2)_<100-x> Granular Films"J. Magn. Magn. Mater. (In Press). (2002)

S.Asakura，S.Ishio，A.Okada，H.Saito：“Co_x(SiO_2)_<100-x>颗粒薄膜的磁畴渗流”J。

H. Ito: "Magnetic Properties of Co-Pt Thin Prepared by Sputtering Method and Applicatibn to MFM Tips"J. Soc. of Mater. Engin. for Resources of Jpn.. 19. 18-22 (2000)

H. Ito：“溅射法制备的Co-Pt薄层的磁性及其在MFM尖端的应用”J。

S.Ishio: "Magnetic anisotropy field H-k and domain structure in L1_0 Fe_xPt_<1-x> films"J. Magn. Magn. Mater. 235. 148-152 (2001)

S.Ishio：“L1_0 Fe_xPt_<1-x> 薄膜中的磁各向异性场 H-k 和磁畴结构”J。

S.Ishlo: "Giant magnetoresistive effect in L1_0 ordered FePt films"J. Magn. Mater. (in press). (2002)

S.Ishlo：“L1_0 有序 FePt 薄膜中的巨磁阻效应”J。

S.Tbmino: "Ferromagnetic Dot Formation in Nonmagnetic Amorphous FeZr Films by Nbn-Contact Atomic Force Microscope"J. Magn, Magn. Mater.. 212. 69-74 (2000)

S.Tbmino：“通过 Nbn 接触原子力显微镜在非磁性非晶 FeZr 薄膜中形成铁磁点”J。