超细纳米晶FePt薄膜的L10有序化转变研究

项目名称： 超细纳米晶FePt薄膜的L10有序化转变研究

项目编号： No.50801020

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 李晓红

作者单位： 河北大学

项目金额： 20万元

中文摘要： 采用X射线衍射分析结合透射电镜等技术分离研究了FePt薄膜L10有序化转变的成核和生长动力学以及原始态晶粒尺寸对FePt薄膜L10有序化转变动力学的影响，揭示了薄膜晶粒尺寸对有序畴的形核和生长的调控作用以及对有序化过程的影响规律。获得了超细纳米晶（2-3 nm）FePt薄膜L10有序化转变的规律。通过FePt薄膜L10有序化转变参数的压力和时间的关系，确定有序化过程中原子的激活体积，弄清了FePt薄膜L10有序化转变过程中原子输运的微观机制。通过提高FePt薄膜L10有序畴的形核率来促进其有序化转变，发展了一项低温制备超细纳米晶(d<10 nm) L10-FePt薄膜的新技术。采用引入界面反应、添加过渡底层等降低了FePt薄膜的L10有序化温度。采用高压技术成功的减小了L10-FePt薄膜的晶粒尺寸和有序畴尺寸并提高了尺寸分布的均匀性，从而调控L10-FePt薄膜的微结构。本项目的完成对弄清FePt薄膜L10有序化转变的微观原子化过程和促进FePt薄膜作为超高密度磁记录介质材料的应用具有重要的意义。

中文关键词： 纳米晶；FePt薄膜；有序化；压力；结构相变

英文摘要： In the present project, the kinetics for the nucleation and growth of the ordered domains of FePt thin films and the effects of the as-deposited grain size on the kinetics have been studied in detail by employing XRD combined with TEM technique, which reveals the mediation effects of the grain size of FePt thin films on the nucleation and growth of L10 ordered domains displaying the L10 ordering characteristic of FePt thin films with an ultra small grain size of 2-3 nm. The mechanism for the atomic transportation in the process of the L10 ordering of FePt thin films has been revealed by determining the atomic activation volume from the dependence of the transition parameters on the annealing pressure and time. By improving the nucleation rate, the ordering process of FePt thin films has been accelerated, which developes a new technique for the preparation of the L10-FePt thin films with ultra small grain size (d&lt;10 nm) at low temperatures. The odering temperature of FePt thin films has been effectively reduced by introducing interface reaction and adding underlayers. High pressure has been successfully applied to reduce both the size of the ordered domains and the grains and improve the size distribution. The present project is of importance for understanding and controlling the atomic process for the L10 ordering of FePt thin films on the nanoscale, and thus of importance for the application of the FePt thin films as ultra high density magnetic recording medium.

英文关键词： Nanocrystals; FePt thin films; Ordering; Pressure; Structural transition