Thermodynamics and Physical Properties of selected Heusler Alloys

技术概述：X2YZ型Heusler化合物和XYZ型半Heusler化合物，其中X和Y是过渡金属，Z是III-V族元素，可以表现出有趣和有用的性质，如形状记忆、热电、铁磁和自旋极化效应。这些类型的未开发化合物可能导致新的机械和电子设备。大量这些化合物的热力学性质，晶体结构和相平衡将被系统地确定。滴量热法将用于测量标准生成热和热容作为温度的函数。相平衡和晶体结构将通过差示扫描量热法、能量色散x射线分析和x射线衍射来确定。数千种可能的成分将通过相图的系统分析和第一性原理计算来快速筛选，以确定要研究的特定系统。所得的热力学数据将编入一个联机数据库，供科学界查阅。这些数据将用于预测相平衡和基准的第一性原理计算这些化合物。从高中到研究生院的学生将通过这些调查进行培训。非技术概述：Heusler合金家族为下一代传感器和执行器提供了希望。这项实验研究将产生对这些有前途的材料的探索和未来发展具有根本重要性的热力学数据。要测量的性质包括热力学性质和物理性质。与世界各地科学家的合作将使成千上万种潜在成分的计算筛选成为可能，以确定那些最适合实验的成分，并将使潜在有用的物理性质的测量成为可能。所产生的数据将通过一个免费的联机数据库提供，这些数据预计将对该领域未来的材料发展和计算预测的基准/验证至关重要。教育培训活动将包括研究生、本科生和高中生。外联活动将包括制作和传播关于实验技术的视频教程。

TECHNICAL SUMMARY:Heusler compounds of type X2YZ and half-Heusler compounds of type XYZ, where X and Y are transition metals and Z is a group III-V element, can exhibit interesting and useful properties, such as shape memory, thermoelectric, ferromagnetic and spin polarization effects. Unexplored compounds of these types could lead to new mechanical and electronic devices. The thermodynamic properties, crystal structures and phase equilibria of a large number of these compounds will be systematically determined. Drop calorimetry will be used to measure the standard heat of formation and heat capacity as a function of temperature. Phase equilibria and crystal structures will be determined using differential scanning calorimetry, energy dispersive X-ray analysis and X-ray diffraction. The thousands of possible compositions will be rapidly screened using systematic analyses of phase diagrams and first-principles calculations to identify specific systems for study. The thermodynamic data obtained will be incorporated into an on-line database for access by the scientific community. The data will be used to predict phase equilibria and to benchmark first principles calculations for these compounds. Students from high school through graduate school will be trained through these investigations.NON-TECHNICAL SUMMARY:The Heusler family of alloys holds promise for the next generation of sensors and actuators. This experimental study will produce thermodynamic data of fundamental importance to the exploration and future development of these promising materials. Properties to be measured include both thermodynamic and physical properties. Collaborations with scientists around the world will enable computational screening of thousands of potential compositions to determine those most appropriate for experiments and will enable the measurement of potentially useful physical properties. The data produced, which are expected to be critical to the field for future material development and benchmarking/validation of computational predictions, will be made available through a free on-line database. Education and training activities will include graduate students, undergraduate students and high-school students. Outreach will include the construction and dissemination of video tutorials on experimental techniques.