Research on magnetization structure stability of magnetic thin films

利用磁力显微镜(MFM)研究了温度对Co合金记录介质磁化结构的影响。用超高真空分子束外延技术在单晶衬底上制备了Co外延薄膜，研究了具有面心立方和六方结构的Co薄膜的基本磁性。得到了以下结果1.通过在真空度低于10^lt；-4&gt；Pa的条件下冷却样品并采用低磁矩探头，MFM的观测分辨率可提高到15-20 nm级别。在-100-300℃的温度范围内，成功地观测到了80-110 GB/in2面密度的高密度磁记录介质的记录磁化结构的变化，阐明了纵向和垂直记录介质加热时磁化结构变化的差异。开发了一种MFM数据分析技术，用于研究磁化结构的纳米尺度变化。采用超高真空分子束外延技术在氧化物单晶衬底上制备了Co外延薄膜，研究了FCC缓冲层和沉积过程中衬底温度对Co薄膜晶体结构的影响。可以控制具有面心立方结构或六方结构的钴薄膜。利用外延Co薄膜系统地研究了薄膜的磁性与晶体结构之间的关系。上述研究成果在国内会议上发表了2篇，在国际会议上发表了3篇，并以5篇论文形式发表在学术期刊上。

The influence of temperature on the magnetization structure of Co-alloy recording media is studied by using a magnetic force microscope (MFM). Preparation of epitaxial Co thin films on single crystal substrates is also tried by using an UHV-MBE to investigate the basic magnetic properties of Co thin films with fcc or hcp crystal structure. The following results are obtained.1. The MFM observation resolution is improved up to 15 -20 nm level, by cooling the sample under a vacuum lower than 10^<-4> Pa and by employing low magnetic moment probe-tips.2. The variation of recorded magnetization structure of high-density magnetic recording media, 80 - 110 Gb/in^2 areal density, has been successfully visualized in a temperature range between -100 - 300 C. The difference in magnetization structure variation upon heating between longitudinal and perpendicular recording media has been clarified.3. An analysis technique of MFM data is developed to investigate the nanometer scale variation of magnetization structure.4. Epitaxial Co thin films are prepared on oxide single crystal substrates by using an UHV-MBE and the effects of fcc-buffer layer and the substrate temperature during film deposition on the crystal structure of Co thin film are clarified. It is possible to control the Co thin film either with fcc or hcp crystal structure. The relationship between the magnetic properties and the crystal structure is systematically studied by using the epitaxial Co thin films.5. The above research results were presented as 2 talks in domestic conferences, 3 talks in international conferences, and were submitted as 5 papers to academic journals.