Novel caloric materials by mastering hysteresis: a material science approach

固态冷却可能是一种完全不同的能源解决方案，在未来取代传统的蒸汽压缩制冷。最有前途的制冷剂不仅在磁化过程中改变其磁性，而且改变其晶体结构。高效磁制冷剂的发展是为了使结构对总熵变的贡献最大化。这样，迟滞是一种不必要的副作用，它会导致损失并阻碍热量效应的充分利用。在这个项目中，我们将深入了解本征磁滞和外征磁滞的来源，从而找到最小化磁滞的策略。此外，我们将开发优化的高性能发热材料，在磁场（μ0H = 1 T）降低的情况下提供大的热效应，这将大大降低磁性冰箱的成本。我们的战略是利用我们在磁/高压材料和器件方面的丰富经验，以及我们在材料科学方面的专业知识，包括新型合成，高级表征以及对磁性，微观结构和热力学的理解。我们专注于最有前途的磁性制冷剂，heusler型ni - mn基，La(Fe,Si)13基和fe2p型MnFeP（Ge,Si）在接近环境条件下运行。

Solid-state cooling could be a radically different energy solution substituting conventional vapor compression refrigeration in the future. The most promising refrigerants do not only change their magnetism during magnetization but also their crystal structure. The development of efficient magnetic refrigerants is to maximize the structural contribution to the total entropy change. In this way, hysteresis is an unwanted side-effect that leads to losses and hinders the full use of caloric effects. In this project, we will develop a thorough understanding of the sources of both intrinsic and extrinsic magnetic hysteresis, so that a strategy to minimize hysteresis can be found. Furthermore, we will develop optimized, high-performance caloric materials that deliver a large caloric effect but in a reduced magnetic field (μ0H = 1 T) that would greatly reduce the cost of a magnetic refrigerator. Our strategy is to use the extensive experience of our work-group in magneto/barocaloric materials and devices, and our expertise in materials science, which covers novel synthesis, advanced characterization, and understanding of magnetic properties, microstructure, and thermodynamics. We focus on the most promising magnetic refrigerants, Heusler-type Ni-Mn-based, La(Fe,Si)13-based and Fe2P-type MnFeP(Ge,Si) operating near to ambient conditions.