Tetragonal distorted Mn3-xGa Heusler compounds: Novel hardmagnetic materials without 4f electrons

四方扭曲 Mn3-xGa Heusler 化合物：无 4f 电子的新型硬磁材料

基本信息

批准号：
249893109
负责人：
Dr. Sabine Wurmehl
金额：
--
依托单位：
Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW) e.V.
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/249893109?language=en
关键词：
Tetragonal distorted Mn3 xGa Heusler

项目摘要

Magnets are vital components of many electromechanical machines and electronic devices. Typical examples are motors and actuators, generators, sound reproduction systems, computer peripherals (disc drives, printers) or as simple magnetic clamps. The principal magnetic materials used today are the Alnico alloys, the ferrites, and the rare-earth (RE) based alloys. For hard magnetic materials, the main requirements are high coercivity, remanence and maximum energy product (BH)max. The wide range of technological applications requires a wide range of permanent magnets with different characteristics of the hysteresis loops and often the final choice is made based on economic considerations. The rare-earth based intermetallic alloys are the most recent and more powerful family of permanent magnets. However, apart from their superior magnetic performance, they have several disadvantages. During their exploration and processing radioactive side-products are generated. Moreover, additional surfactants are necessary to protect the RE from oxidation, which causes higher costs and additional environmental pollution. SE materials have a comparably low Curie temperature (NdFeB, TC=583 K) which also limits their use. Most importantly, RE materials are very expensive and the price for SE materials is currently even more increasing, which makes a substitution for RE materials highly desirable. A clear strategy to overcome these difficulties is to develop new rare earth free magnets with appreciable magnetic properties. Towards this direction substantial attention has been given to Mn3-xGa Heusler alloys which, despite the lack of RE elements exhibit ferrimagnetism and large magneto-crystalline anisotropy. Hence, the advantage of the Mn-Ga materials are their high Curie temperature and considerable magnetic anisotropy combined with a higher chemical stability compared to the RE magnets. Contradicting claims in the literature regarding the coexistence of different crystalline phases in Mn3-xGa alloys call for more thorough studies of the structural, microstructural and magnetic properties of these compounds and to elaborate on the structure-properties-relations. In this project, we plan to explore und understand the origin of the hardmagnetic properties in Mn3-xGa. This will be done by tailoring the preparation process, investigating the (magnetic) structure and microstructure, by systematic substitution of both Mn and Ga, and by relating those properties to the magnetic key properties (remanence, coercive fields, maximum energy product) to assign a new rare earth free permanent magnet with high magnetic performance.

磁铁是许多机电机器和电子设备的重要组成部分。典型的例子是电动机和执行器，发电机，声音繁殖系统，计算机外围设备（盘式驱动器，打印机）或简单的磁夹。当今使用的主要磁性材料是Alnico合金，铁氧体和稀土（RE）合金。对于硬磁性材料，主要要求是高强度，避孕和最大能量产物（BH）最大。广泛的技术应用需要具有不同特征的磁滞循环特征的广泛磁铁，并且通常是根据经济考虑做出的最终选择。基于稀土的金属合金是最近，更强大的永久磁铁系列。但是，除了其出色的磁性性能外，它们还有几个缺点。在探索和加工期间，产生了放射性副产品。此外，需要额外的表面活性剂来保护RE免受氧化的影响，这会导致更高的成本和额外的环境污染。 SE材料的居里温度相对低（NDFEB，TC = 583 K），这也限制了它们的使用。最重要的是，RE材料非常昂贵，目前，SE材料的价格也更加上涨，这使得替代了RE材料。克服这些困难的明确策略是开发具有可观的磁性特性的新的稀土磁铁。向这个方向朝着MN3-XGA Heusler合金引起了很大的关注，尽管缺乏元素表现出铁磁性和较大的磁性晶状体各向异性。因此，与RE磁体相比，MN-GA材料的优势是它们的高咖喱温度和相当大的磁各向异性以及更高的化学稳定性。在文献中，关于MN3-XGA合金中不同晶相共存的主张矛盾，要求对这些化合物的结构，微结构和磁性性能进行更彻底的研究，并详细介绍结构 - 质体关系。在这个项目中，我们计划探索和了解MN3-XGA中硬磁性能的起源。这将通过定制制备过程，通过系统的替换MN和GA来调查（磁性）结构和微观结构，以及将这些特性与磁性钥匙特性（Remanence，强制性磁场，最大能量产物）联系起来，以分配具有高磁性性能的新的稀土永久磁铁。