CAREER: Microstructure and Mean Stress Evolution in Atomistic Ordering Thin Films

技术支持：随着对开发纳米器件的需求不断增加，在“按比例缩小”金属间化合物的同时保持其原子级稳定性存在几个重大挑战。这对磁存储行业来说尤其重要，因为磁存储行业需要新材料来实现每平方英寸太比特范围内的超高存储密度。高磁晶各向异性合金FePt、CoPt、FePd和MnAl是下一代磁数据存储系统的候选金属间化合物。当这些金属被溅射沉积为纳米颗粒微观结构时，它们采用亚稳相，需要高温退火以形成适当的化学有序相。应力可以对纳米尺度下的相和微观结构产生显著影响。在纳米尺度上缺乏足够的原子微观结构表征使得这种相变没有得到很好的理解。研究将提供残余应力对纳米范围内有序合金的形核和结构稳定性的影响。原子探针断层扫描（APT），高分辨率透射电子显微镜，并在原位薄膜应力监测将被耦合到解决的影响，薄膜应力的早期阶段的秩序，成分偏析，和薄膜生长。通过将薄膜的残余应力状态与其微观结构和有序相演化相关联，将实现金属间稳定性与尺寸的关系。非技术性：结果将对磁信息存储的实际方面产生重大影响。该研究将平衡教学，学术和服务于大学和科学界。将制定一项协同计划，用于研究生，本科生和高中生的专业发展和招聘，进入材料科学与工程。它将包括高中暑期研究经验，以及历史上黑人学院和大学（HBCU）的教师的教材科学。HBCU教师的暑期研究休假将纳入研究。研究将通过亚拉巴马大学信息技术材料中心（MINT）协调的研讨会传播到磁性行业。

TECHNICAL: With an ever-increasing demand for developing nanoscale devices, several significant challenges exist in 'scaling-down' intermetallics while maintaining their atomic-order stability. This is of particular interest to the magnetic storage industry, which needs new materials to achieve ultra-high storage density in the terabit per square-inch range. High magnetocrystalline anisotropy alloys FePt, CoPt, FePd and MnAl are candidate intermetallic compounds for the next-generation of magnetic data storage systems. When these metals are sputtered deposited as a nanogranular microstructure, they adopt a metastable phase requiring a high temperature anneal to form the appropriate chemically ordered phase. Stress can have a significant influence on the phase and microstructure at the nanoscale. The lack of sufficient atomistic microstructural characterization at the nanoscale has made this phase transformation not well understood. Research will provide the influence of residual stress on the nucleation and structural stability of ordered alloys in the nanometer regime. Atom Probe Tomography (APT), high-resolution transmission electron microscopy, and in-situ thin film stress monitoring will be coupled to address the effect of film stress on the early stages of ordering, composition segregation, and film growth. By correlating the residual stress state of a film to its microstructure and ordered phase evolution, the intermetallic stability relationship to size will be realized. NON-TECHNICAL: Results will have a major impact on the practical aspects of magnetic information storage. The research will balance teaching, scholarship, and service to the university and the scientific community. A synergistic program for the professional development and recruitment of graduate, undergraduate, and high school students into materials science and engineering will be developed. It will include a high school summer research experience, and teaching materials science to faculty from historically black colleges and universities (HBCU). A summer research sabbatical for HBCU faculty will be incorporated into the research. Research will be disseminated to the magnetic industry through workshops coordinated by the Center for Materials for Information Technology (MINT) at University of Alabama.