High Density Information Storage Materials Research using Laser Ablation Technique

本研究旨在探索用于高密度数据存储(包括磁记录和磁光记录)的贵金属材料。为此，重要的是将磁、磁光和结构特性与在良好控制条件下制造的记录介质的记录性能相关联。本文提出了一种新的激光烧蚀加工系统的设计方案，并成功地研制出了一套新的激光烧蚀系统。与市面上销售的系统相比，该系统具有独特的特点。首先，所选择的材料的目标可以在沉积过程中旋转，以使得能够连续地改变膜成分。因此，可以根据需要优化薄膜组合物的磁性，从而获得高记录性能。由于靶板与衬底之间的距离较大，在2“d…上，厚度和成分的均匀性优于5%。更长的距离。此外，还配备了现场测量磁光特性的能力。主要对锶铁氧体薄膜和Co-Ag颗粒膜进行了实验研究，结果表明：1.在650-800℃热处理2小时后，锶铁氧体薄膜表现出较高的垂直磁各向异性(*106 erg/cc)。整体的磁性能被发现在未来的高密度垂直磁记录中是非常有前途的。需要进一步优化制备工艺以获得更好的磁性能。2.当Co含量在20at%左右时，Co-Ag颗粒薄膜具有很大的垂直磁各向异性。磁力显微镜对磁畴的观察支持这种高的磁各向异性的存在。3.结果表明，所开发的激光沉积系统被证明能够探索贵金属材料，不仅可用于数据存储应用，还可用于其他设备。较少

The present research aims to investigate into noble materials for high density data storage (both magnetic and magneto-optical recordings). For this purpose, it is important to correlate magnetic, magneto-optical and structural properties with recording performance of recording media fabricated under well-controlled conditions. A proposal to develop a new fabrication system using a laser ablation method was made in the present study.A newly designed laser ablation system using a Nd : YAG laser (1W) has been successfully developed. This system has unique features as compared with commercially available ones. First of all, a target of materials of choice can be rotated during deposition so as to enable to change film composition continuously. Therefore, one can optimize film composition for magnetic properties as desired, leading to high recording performance. Because of a large distance between target and substrate, the uniformity in thickness and composition is better than 5% over 2" d … More iameter. Also, in-situ capability for measuring magneto-optical properties is equipped. The system has been proved to be controllable and reproducible for fabrication condition.The experiments were carried out mainly for Sr-Ferrite thin films and Co-Ag granular films.The results may be summarized as follows :1.Sr-Ferrite films exhibit high perpendicular magnetic anisotropy (*10 6 erg/cc) after annealed at 650-800C for 2 hrs. The over all magnetic properties are found to be very promising for future high density vertical magnetic recording. Further optimization for fabrication processes is needed for better magnetic behaviors.2.Co-Ag granular thin films exhibit a large perpendicular magnetic anisotropy when Cocontents are around 20at%. Observations of magnetic domains by magnetic force microscopy supports the existence of such a high magnetic anisotropy. Very little understanding of the origin is obtained, which remains for further detailed studies.3.The results demonstrated indicate that the laser deposition system developed is proved to capable for exploring noble materials for not only data storage applications but also other devices. Less