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

职业：原子有序薄膜中的微观结构和平均应力演化

• 批准号: 0547445
• 负责人: Gregory Thompson
• 金额: $ 49.72万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0547445&HistoricalAwards=false
• 关键词: CAREER; Microstructure; Mean; Stress; Evolution

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.

技术：随着开发纳米级器件的需求不断增加，在保持其原子顺序稳定性的同时，“缩小”金属间化合物存在几个重大挑战。这对于需要新材料来实现超高存储密度（每平方英寸太比特）的磁存储行业来说是特别有趣的。高磁晶各向异性合金FePt， CoPt， FePd和MnAl是下一代磁性数据存储系统的候选金属间化合物。当这些金属以纳米颗粒的微观结构溅射沉积时，它们采用亚稳相，需要高温退火才能形成适当的化学有序相。在纳米尺度上，应力对相和微观结构有显著影响。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。研究残余应力对纳米有序合金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和原位薄膜应力监测将相结合，以解决薄膜应力对有序、成分偏析和薄膜生长的早期阶段的影响。通过将薄膜的残余应力状态与其微观结构和有序相演化联系起来，可以实现金属间化合物与尺寸的稳定性关系。非技术性：结果将对磁信息存储的实际方面产生重大影响。这项研究将平衡教学、学术以及对大学和科学界的服务。将为材料科学与工程专业的研究生、本科生和高中生的专业发展和招聘制定一个协同计划。它将包括高中暑期研究经历，以及向传统黑人学院和大学（HBCU）的教师讲授材料科学。HBCU教师的暑期研究休假将纳入研究。研究将通过由阿拉巴马大学信息技术材料中心（MINT）协调的讲习班向磁性工业传播。