基于准同型相界原理的高性能磁致伸缩材料研究

Magnetostrictive material is a key functional material due to its usability for transducer and sensor devices. With the improvement of high-tech industry and national defenseindustry, it becomes more and more urgent to develop the high-performance magnetostrictive material with the properties of narrow magnetostrictive hysteresis, high figure of merit and large magnetostriction. However, the magnetostrictive materials manufactured from traditional principle cannot simultaneously achieve these three properties and thus become a bottle-neck problem for the design of high-performance magnetostrictive material. Therefore, it is necessary to explore the magnetostrictive materials from the new principles. Here, based on our previous results about magnetostriction, we propose a proposal to study the high-performance magnetostrictive materials based on magnetic morphotropic phase boundary (MPB). By controlling composition, the method for promoting the phase instability will be used to design the new magnetostrictive materials and to improve their properties. Based on above studies, the general rules for the design of high-performance magnetostrictive materials can be expected. According to these rules, we will fabricate the magnetostrictive materials in the systems of Laves and Heusler magnetic alloys and further study other related physical problems, such as thermal properties, mechanical properties, electrical properties, and so on. Through this proposal, we look forward to realize the following three goals. First, we will clarify the underlying physical mechanism of MPB principle. Second, several general rules for the design of high-performance magnetostriction will be summarized. Third, we will fabricatethe high-performance magnetostrictive materials with the properties of narrow magnetostrictive hysteresis, high figure of merit and large magnetostriction.

磁致伸缩材料是制造换能器和传感器的重要磁性功能材料。随着现代产业技术和国防技术对微位移控制系统的要求日益提高，迫切需要开发具有窄滞后、高灵敏度和大应变的高性能磁致伸缩材料。本项目是在我们前期已取得研究成果基础之上，提出基于准同型相界原理开发高性能磁致伸缩材料的研究。项目研究从材料组分调控出发，采取准同型相界中临界相变能促进相结构失稳的研究思路对磁致伸缩材料进行理论设计，并理论归纳出提高磁致伸缩材料性能的普适准则。在此基础之上，采用多种材料制备方法在Laves型RT2稀土过渡族化合物和Heusler型Ni2MnX合金中实现新型磁致伸缩材料的开发，并对其热、电、力等相关物理问题进行深入研究。通过本项目研究，可阐释磁致伸缩效应的准同型相界原理的物理机制，并最终制备出具有窄滞后、高灵敏度和大应变的高性能磁致伸缩材料；同时为寻找热、力、电等其它具有高磁响应效应（如磁热效应等）材料提供理论依据。

磁致伸缩材料是制造换能器和传感器的重要磁性功能材料。随着现代产业技术和国防技术对微位移控制系统的要求日益提高，迫切需要开发具有窄滞后、高灵敏度和大应变的高性能磁致伸缩材料。本项目是在我们前期已取得研究成果基础之上，提出基于准同型相界原理开发高性能磁致伸缩材料的研究。项目研究从材料组分调控出发，采取准同型相界中临界相变能促进相结构失稳的研究思路对磁致伸缩材料进行理论设计，并理论归纳出提高磁致伸缩材料性能的普适准则。在本项目的研究过程中，我们主要设计并制备了基于Laves型RT2稀土过渡族化合物和Heusler型Ni2MnX两种材料的磁性准同型相界，主要分析了准同型相界附近的高磁致伸缩效应，并利用Landau相变理论和第一性原理计算了其高性能的物理机制。在次基础上对其热、电、力等相关物理问题进行深入研究，发现了相界附近的小热滞，大制冷能力的磁热效应和较大的自发交换偏置效应。最终，通过本项目研究，我们阐释磁致伸缩效应的准同型相界原理的物理机制，并制备出具有窄滞后、高灵敏度和大应变的高性能磁致伸缩材料；同时为磁热效应、交换偏置效应等物理现象提供了理论依据。

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