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。这些日新月异的进步从根本上改变了信息技术和生活方式。这些信息存储在微小的磁铁中，就像纳米大小的指南针。由于每一位信息都存储在越来越小的体积上，因此使用在极小维度上仍然稳定的材料来抵御热效应是至关重要的。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，实现高磁各向异性材料在下一代超高密度磁记录介质和无稀土、无贵金属永磁体中的应用。加州大学戴维斯分校和希捷公司之间的这一目标合作伙伴关系提供了一个令人兴奋的机会，可以迅速将研究成果转化为技术。这可能会加快新兴的热辅助磁记录技术的适应速度。更强大的永磁体方面的进展将影响许多工业部门，包括混合动力和电动汽车、磁悬浮列车、风力涡轮机、电力储存、磁制冷等。除了在大学和国家实验室和用户设施中接触到极好的研究经验外，这一伙伴关系还提供了培训行业研发实验室初级研究人员的机会。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性会议上的其他具体计划，扩大代表不足群体的参与。高磁各向异性材料在下一代超高密度热辅助磁记录介质以及高能量密度永磁体中具有关键应用。L10相中有序的FePT合金是记录介质应用的理想候选者。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。该项目将利用原子尺度多层溅射和快速热退火来获得高磁各向异性的L10FePT基薄膜。这些材料的磁性能将通过适当调整有效价电子数来实现所需的高各向异性、大饱和磁化强度和低居里温度。这些方法将被扩展到实现L10 FeNi薄膜，这是一种使用丰富的稀土元素的替代类型的永磁体。对这些薄膜中的无序-有序相变有了真正的认识，并对其相组成进行了定量的评价。加州大学戴维斯分校和希捷的合作伙伴关系将有助于获得易于合成、原子尺度各向异性可控、开关场分布最小的L10FePT和FeNi基合金。这种材料在加快适应新出现的超高密度热辅助磁记录技术以及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.