GOALI: High Magnetic Anisotropy Materials for Ultrahigh Density Heat-assisted Magnetic Recording Media.

在过去的60年里，磁记录的面密度增加了8个数量级。这些快速的进步从根本上改变了信息技术和生活方式。信息存储在微小的磁铁中，就像纳米尺寸的指南针一样。由于每个比特的信息都存储在一个越来越小的体积上，因此必须使用在极小的尺寸上仍然稳定的材料来抵抗热效应。这种材料特性被称为磁各向异性，它将磁矩固定在适当的位置，使其能够实际使用。本项目旨在利用方便、良性的合成条件，结合对材料性能的控制，实现具有高磁各向异性的材料，面向下一代超高密度磁记录介质和无稀土、无贵金属永磁体的应用。加州大学戴维斯分校和希捷之间的GOALI合作伙伴关系为将研究成果迅速转化为技术提供了令人兴奋的机会。这可能会加速新兴的热辅助磁记录技术的适应。更强大的永磁体的进步将影响许多行业，包括混合动力和电动汽车、磁悬浮列车、风力涡轮机、电力存储、磁制冷等。该伙伴关系还提供了在工业研究和开发实验室培训初级研究人员的机会，此外还提供了在大学和国家实验室和用户设施中获得研究经验的绝佳机会。该团队计划发起并积极参与各种努力，通过实习、提供研究生课程、与希捷交换访问以及磁学会议上的其他具体项目，扩大代表性不足群体的参与。高磁各向异性材料在下一代超高密度热辅助磁记录介质和高能量密度永磁体中有着重要的应用。L10相的有序FePt合金是记录介质应用的理想候选材料。然而，一个关键的挑战是将沉积的低各向异性相转变为所需的高各向异性相所需的高退火温度。本项目将采用原子尺度多层溅射和快速热退火技术制备高磁各向异性L10 fept基薄膜。利用三元fept基合金，通过适当调整有效价电子数，可以实现高各向异性、大饱和磁化强度和低居里温度的磁性能。这些方法将被扩展到实现L10 FeNi薄膜，这是一种使用富土元素的替代永磁体。将获得对这些薄膜中无序-有序相变的真正理解，并获得相分数的定量评价。加州大学戴维斯分校和希捷的合作将有助于实现易于合成的L10 FePt和FeNi基合金，这些合金在原子尺度上具有可控的各向异性和最小的开关场分布。这些材料在加速适应新兴的超高密度热辅助磁记录技术和实现无稀土和无贵金属的高能量密度永磁体方面具有潜在的变革性技术影响。

Over the last six decades, the areal density of magnetic recording has increased by eight orders of magnitude. These rapid advancements have fundamentally changed information technology and the way of life. The information is stored in tiny magnets, like compasses with nanometer sizes. As each bit of information is stored over an ever-smaller volume, it is essential to use materials that are still stable at extremely small dimensions against thermal effects. This material property is known as the magnetic anisotropy, which anchors magnetic moments in place, enabling their practical use. This project aims at realizing materials with high magnetic anisotropy using convenient and benign synthesis conditions, combined with control over the material properties, towards applications in next generation ultrahigh density magnetic recording media and rare-earth-free and precious-metal-free permanent magnets. This GOALI partnership between U.C. Davis and Seagate offers an exciting opportunity to rapidly transfer research results into technology. This would potentially speed up the adaptation of the emerging heat-assisted magnetic recording technology. Advances in more powerful permanent magnets would impact numerous industry sectors, including hybrid and electric vehicles, magnetically levitated trains, wind turbines, power storage, magnetic refrigeration, etc. The partnership also provides opportunities to train junior researchers in industry research and development laboratories, in addition to excellent exposure to research experience in university and national laboratory and user facilities. The team plans to initiate and actively participate in a variety of efforts to broaden participation from underrepresented groups through internships, graduate course offering, exchange visits with Seagate, and other specific programs at the Magnetism Conference.High magnetic anisotropy materials have critical applications in next generation ultrahigh density heat-assisted magnetic recording media as well as high energy density permanent magnets. Alloys of ordered FePt in the L10 phase is an ideal candidate for recording media applications. However, a critical challenge has been the high annealing temperature necessary to transform the as-deposited low anisotropy phase into the desirable high anisotropy one. This project will achieve high magnetic anisotropy L10 FePt-based thin films using atomic-scale multilayer sputtering and rapid thermal annealing. Magnetic properties of these materials will be tailored to achieve the desirable high anisotropy, large saturation magnetization, and low Curie temperature using ternary FePt-based alloys through proper tuning of the effective valence electron number. These approaches will be extended to realize L10 FeNi films that are alternative type of permanent magnets using earth abundant elements. A true understanding of the disorder-order phase transformation in these thin films will be gained, and quantitative evaluation of the phase fractions will be obtained. The partnership between U.C. Davis and Seagate will help to achieve L10 FePt and FeNi based alloys that can be readily synthesized, with controlled anisotropy at the atomic scale and minimized switching field distribution. Such materials have potentially transformative technological impacts, in speeding up the adaption for the emerging ultrahigh density heat-assisted magnetic recording technology and in the realization of high energy density permanent magnets that are rare-earth-free and precious-metal-free.