Heusler铁磁合金中的磁畴动态特性和马氏体结构相变研究

项目名称： Heusler铁磁合金中的磁畴动态特性和马氏体结构相变研究

项目编号： No.11274368

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 田焕芳

作者单位： 中国科学院物理研究所

项目金额： 86万元

中文摘要： 铁磁形状记忆合金是一类重要的智能材料，它具有独特的形状恢复、自我驱动和机械输出特性，在航空、医疗、交通和能源领域有广泛的用途。这种铁磁材料的形状记忆效应和低温马氏体相的结构相变以及逆相变的性能密切相关，我们初步研究表明，在低温区，系统存在丰富的结构现象和磁畴演变行为。其中马氏体相变和磁相变的关联与竞争是很重要的科学问题。本项目主要关注的问题包括：（1）深入研究不同组分的Heusler合金（包括Ni2FeGa和Mn50Ni40Sn10）中丰富的微结构现象和相变过程，分析结构相变的特点和规律。（2）利用原位Lorentz TEM技术观测这种材料铁磁相变的磁有序过程和磁畴结构。（3）系统分析马氏体结构相变诱导的铁磁-反铁磁相变，探索磁畴和马氏体微结构畴之间竞争和共存。在上述系统实验结果基础上深入研究Heusler合金的结构和物理性能之间的关联，对其重要结构现象和相变给出合理的解释。

中文关键词： 形状记忆合金；马氏体相变；结构动力学；超快电子显微镜；

英文摘要： Ferromagnetic shape memory alloys as a typical smart material have been widely used in various fields, such as aerospace, biomedical, traffic and energy because of their unique shape recovery, self-driven and mechanical output performance. The special shape recovery effect is essentally in correaltion with the martensitic phase transition and its reversibiblity. Our recent studies revealed that the coupling and competation between martensitic and magnetic transitions at low-temperatures are critical issues for understanding the fundemental properties of this kind of materials. In this project, we will focus on the following issues: (1) investigations of the microstructure and phase transformations in Heusler (including Ni2FeGa and Mn50Ni40Sn10), and analyzing the characteristic features for the low temperature phase transformations. (2) Observations of magnetic domains/walls by using in-situ TEM and Lorentz TEM techniques. (3) Analyses of the ferromagnetic - antiferromagnetic transition induced by the martensitic phase transformation, exploring the competition and coexistence between the magnetic domains and martensitic domains. We will also discuss the relationship between microstructure and physical properties based on the our experimental results.

英文关键词： shape memory alloy；martensitic transformation；structural dynamic；ultrafast transmission electron microscope；