CAREER: Magnetic Anisotropy in Cobalt Alloy Films used in Hard Disk Recording Media

9875545罗斯这个职业生涯的建议关注薄钴合金薄膜用于硬盘记录介质的磁性能。 该提案的研究部分的目标是确定面内磁各向异性的起源，这是在非平面衬底上沉积的薄膜中观察到的，并且在确定硬盘设备的记录性能方面至关重要。 与此应用相关的教育目标旨在让学生为数据存储行业的职业生涯做好准备。数据以写入溅射钴合金薄膜的磁化模式存储在硬盘中，通常沉积在铬底层上。 为了改善磁头-磁盘界面的摩擦学性能，通常在溅射前将表面划痕引入到硬盘基板中。 然而，当Cr/Co合金双层膜溅射到有划痕或沟槽的基底上时，发现平行于沟槽的面内矫顽力、剩磁和矩形度较高。 这种各向异性可能很大，即使是浅槽，但各向异性的起源还没有很好地理解。 这项研究的目的是澄清磁性薄膜的结构是如何受到衬底形貌的影响，并解释这是如何导致磁各向异性和影响器件性能。 此外，在确定磁性能的Cr和Co合金之间的外延关系的重要性将被调查。 这项研究具有重要意义的硬盘行业以及在其他磁性薄膜器件，如传感器或元件的磁阻readback heads.The拟议的工作将使用独特的亚微米光刻设施建立在纳米结构实验室在麻省理工学院准备大面积基板与控制亚微米形貌。 这将允许测量由在良好限定的衬底特征上的沉积产生的各向异性。 拟议工作的主要目标是：- 量化特定基底地形特征的贡献（凹槽、脊、台阶）与Co合金膜中的磁各向异性的关系-将各向异性与膜的结构特征（包括晶粒形状、c轴取向、内应力以及Cr和Co合金层之间的外延关系）相关联-基于这些发现，提出用于控制薄膜中的磁各向异性的方法-与工业伙伴合作，制造具有受控表面特征的磁介质，，以展示如何透过设计表面形貌来改变硬盘的磁记录特性。本建议书的教育内容将集中于发展连接该计划旨在加强大学与业界之间的知识转移，并提升学生在这个重要行业的就业前景。 这个数十亿美元的行业提供了许多就业机会，但其对准备充分的毕业生的强烈需求并没有得到传统的电子材料科学和工程教育和培训的满足。 课程开发将包括在讲座和实验室课程中强调磁性设备和材料，引入短期课程，包括来自行业的客座讲师和对当地公司的访问，创建磁性设备兴趣小组，以帮助学生和工业研究小组有效地互动，并为高中教师开展外联活动。

9875545RossThis CAREER proposal concerns the magnetic properties of thin cobalt-alloy films used in hard disk recording media. The goals of the research component of the proposal are to determine the origin of in-plane magnetic anisotropy, which is observed in films deposited over non-planar substrates, and which is critical in determining the recording performance of hard disk devices. The educational goals, related to this application, are designed to equip students for careers in the data storage industry.Data are stored in hard disks as magnetization patterns written into a sputtered cobalt-alloy thin film, usually deposited onto a chromium underlayer. Surface scratches are commonly introduced into hard disk substrates before sputtering to improve the tribological behavior of the head-disk interface. However, when the Cr/Co-alloy bilayer film is sputtered onto a scratched or grooved substrate, it is found that the in-plane coercivity, remanence and squareness are higher parallel to the grooves. This anisotropy can be large, even for shallow grooves, but the origin of the anisotropy is not well understood. The goal of this research is to clarify how the structure of the magnetic films is affected by substrate topography, and to explain how this leads to magnetic anisotropy and affects device performance. Additionally, the importance of the epitaxial relation between the Cr and the Co-alloy in determining magnetic properties will be investigated. This research has significance in the hard disk industry as well as in other magnetic thin-film devices such as sensors or elements in magnetoresistive readback heads.The proposed work will use unique submicron lithography facilities established at the NanoStructures Laboratory at MIT to prepare large-area substrates with controlled submicron topographies. This will allow the anisotropy created by deposition over well-defined substrate features to be measured. The major objectives of the proposed work are: - to quantify the contribution of specific substrate topographic features (grooves, ridges, steps) to magnetic anisotropy in Co-alloy films - to relate the anisotropy to structural features of the film, including grain shape, c-axis orientation, internal stress, and the epitaxial relation between the Cr and Co-alloy layers - based on these findings, to propose methods for controlling magnetic anisotropy in thin films - in collaboration with an industrial partner, to fabricate magnetic media with controlled surface features, in order to demonstrate how the magnetic recording properties of a hard disk can be modified by design of the surface topography.The educational element of this proposal will focus on development of links between students and the magnetics industry, with the aim of strengthening knowledge transfer between university and industry and enhancing the career prospects of students in this important sector. This multi-billion dollar industry provides many opportunities for employment, yet its strong demands for well-prepared graduates are not being met by traditional education and training in electronic materials science and engineering. Course development will include an emphasis on magnetic devices and materials in lectures and laboratory classes, the introduction of a short course including guest lecturers from industry and a visit to a local company, the creation of a Magnetic Devices interest group to help students and industrial research groups interact effectively, and outreach activities to high school teachers.***