Synthesis, structure and properties of responsive solid-state materials

响应性材料在恒定或可变的外加力或场下表现出独特的物理响应。这种物理响应与固态相突出的机械性能相结合，产生了在工业和消费者层面都有应用的功能材料。这项研究将集中在两个响应性固态材料领域：磁热和热电相。磁热材料在磁场变化时通过改变温度来响应，可用于磁制冷，比传统的蒸气循环制冷效率更高。热电材料在温度梯度作用下产生电压，或在电流通过时进行冷却/加热。目前，热电材料被用于深空任务、远程天气和导航系统的发电，以及电子设备和汽车座椅的冷却。由于一半的能源作为废热损失，研究工作开始专注于通过热电发电机回收部分能源，特别是在汽车和烤箱中。 拟议研究的短期目标将是发现和表征新的、高性能的热电和磁热材料。从长远来看，我们的目标是加深对这些类型材料的组成-结构-性能关系的理解，并将所获得的知识用于快速和有针对性的新材料设计。 在热电材料中，我们将重点合成通式为LNM(Sb，Bi)NOM的镧系(Ln)锑化物和铋系次氧化物。这些相可以归类为“电子-晶体声子-玻璃”材料，因为它们是良好的电导体，而它们的导热系数非常低，接近非晶态材料的导热系数。一些LNM(Sb，Bi)NOM材料表现出新颖的电荷输运机制，我们希望利用这些机制来优化它们的热电性能。对LNM(Sb，Bi)NOM亚氧化物的研究是我们小组发起的，我们希望保持我们在这一领域的领先地位。 在磁热领域，我们将致力于新的极性金属间化合物材料的定向合成，其中铁磁有序与室温或接近室温的结构转变相耦合。我们建议利用价电子浓度和尺寸效应来调整新的磁热材料的结构和磁性。这些方法是我们团队的先驱，我们将把它们应用于制备新颖的高性能相。

Responsive materials exhibit unique physical responses under constant or variable applied forces or fields. Combination of such physical responses with outstanding mechanical properties of solid-state phases yields functional materials that find applications both at the industrial and consumer levels. The research will focus on two areas of responsive solid-state materials: magnetocaloric and thermoelectric phases. Magnetocaloric materials respond by changing their temperature when the magnetic field is varied and can be used for magnetic cooling, which offers better efficiency than conventional vapour-cycle refrigeration. Thermoelectric materials generate voltage when subject to a temperature gradient or perform cooling/heating when current is passed through them. Currently, thermoelectric materials are used for power generation in deep-space mission, remote weather and navigation systems and for cooling in electronic devices and car seats. And since half of the energy is lost as a waste heat, research efforts start to focus on recovering some of this energy, especially in cars and ovens, through thermoelectric generators. The short term goals of the proposed research will be discovery and characterization of novel, high-performance thermoelectric and magnetocaloric materials. In the long run, we aim to develop a deeper understanding of the composition-structure-property relationship in these types of materials, and to use the obtained knowledge for the rapid and targeted design of new materials. Among the thermoelectric materials, we will focus on the synthesis of lanthanoid (Ln) antimonide and bismuthide suboxides with the general formula Lnm(Sb,Bi)nOm. These phases may be classified as "electron-crystal phonon-glass" materials, as they are good electrical conductors, while their thermal conductivity is very low and is approaching that of amorphous materials. Some of the Lnm(Sb,Bi)nOm materials display novel charge transport mechanisms and we want to use these mechanisms to optimize their thermoelectric properties. The research on the Lnm(Sb,Bi)nOm suboxides was initiated in our group and we would like to maintain our leading role in this area. In the magnetocaloric field, we will pursue targeted synthesis of new polar intermetallic materials, in which a ferromagnetic ordering is coupled to a structural transition at or near room temperature. We proposed to utilize the valence electron concentration and size effects to tune structural and magnetic properties of new magnetocaloric materials. These approaches were pioneered in our group and we will apply them to prepare novel high-performance phases.