EAGER: CRYO: New Quantum Elastocaloric Demagnetization Refrigeration for the Millikelvin Range

该项目由化学、生物工程、环境和运输系统部以及材料研究部共同支持。人们越来越需要开发可冷却到1开尔文以下的替代制冷技术，以支持量子传感器和量子计算机等新兴应用。目前，液氦制冷机主要用于达到低于1开尔文的温度。由于氦的日益稀缺以及当前技术缺乏便携性或可扩展性，替代冷却方法受到极大关注。固态制冷技术，如磁性固体材料通过减少和增加磁场的循环冷却的技术，在部分取代氦技术方面取得了一定的成功。然而，它具有显著的缺点，包括几特斯拉的高磁场要求。本计画提出一种基于机械应变固态磁性材料的低场冷却技术。这种方法预计是可持续的，便携式的，并部署在电子芯片级，提供了一个可扩展性的路线。在这个项目中，一组不同的学生将接受热，材料和量子科学的培训。这项培训将通过开发一个新的课程，重点是在先进的本科教学实验室低温冷却，通过麦克奈尔计划为代表性不足的本科生和通过研究生水平的研究项目的研究项目。暑期研究机会将提供给当地高中教师，以开发现代热科学的教育演示作为量子支持的研究领域。高风险高回报工作的总体目标在这里提出，这是由化学，生物工程，环境和运输系统部门和材料研究部门共同支持，是实现一种新的固态毫开尔文量子弹性绝热制冷技术，其中冷却循环将通过周期性地施加弹性应变/应力来实现，没有或具有小磁场。在这个项目中，弹性应力/应变调谐将用于在一种特殊类型的磁性材料（称为受抑磁体）中诱导近零温度相变。因此，这种新方法有望以高效率提供远低于1开尔文的冷却。为了评估薄膜，单晶体和块状陶瓷的受抑磁体，一个阵列的应变下的材料的独特适应的表征工具将采用：超导量子干涉器件显微镜，热成像，交流热容，磁化等建议应变驱动的冷却技术预计将提供上级冷却功率和较低的温度相比，其他一些固态冷却技术。量子弹性绝热制冷方法有可能成为取代其他平台的突破性发现，特别是在低磁场和片上可扩展应用中，并可能对节能电子产品产生变革性影响，该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的评估被认为值得支持。影响审查标准。

This project is jointly supported by the Division of Chemical, Bioengineering, Environmental and Transport Systems and the Division of Materials Research.There is a growing demand to develop alternative refrigeration technology that can cool below 1 Kelvin for supporting emerging applications, such as quantum sensors and quantum computers. Currently, liquid helium refrigerators are mostly used to reach temperatures below 1 Kelvin. Due to the increasing scarcity of helium and lack of portability or scalability of the current technologies, alternative cooling methods are of great interest. Solid-state refrigeration technology, such as the one in which magnetic solid materials are cooled via cycles of decreasing and increasing magnetic field has been somewhat successful in partly replacing helium technology. However, it has significant drawbacks, including high magnetic field requirement of several Tesla. This project puts forward a low-field cooling technology based on mechanically strained solid-state magnetic materials. This approach is projected to be sustainable, portable, and deployed at the electronic chip level, providing a route to scalability. During this project, a diverse group of students will be trained in thermal, material and quantum sciences. This training will be provided through the development of a new curriculum focusing on low temperature cooling in advanced undergraduate teaching laboratory, in research projects through the McNair program for underrepresented undergraduate students and through graduate-level research projects. Summer research opportunities will be provided for local high school teachers to develop educational demos in modern thermal science as a quantum-supporting area of research.The overarching goal of the high-risk high-reward work propose here, which is jointly supported by the Division of Chemical, Bioengineering, Environmental and Transport Systems and the Division of Materials Research, is to realize a new solid-state millikelvin Quantum Elastocaloric Adiabatic Refrigeration technology in which a cooling cycle will be achieved via periodic application of elastic strain/stress, without or with small magnetic field. In this project, elastic stress/strain tuning will be used to induce near-zero temperature phase transitions in a special type of magnetic materials called frustrated magnets. Thus, this new method is expected to provide cooling well below 1 Kelvin with high efficiency. To evaluate thin films, single crystals and bulk ceramics of frustrated magnets, an array of uniquely adapted characterization tools for materials under strain will be employed: superconducting quantum interference device microscopy, thermal imaging, ac heat capacity, magnetization etc. The proposed strain-driven cooling technology is expected to provide superior cooling power and lower temperature in comparison to some other solid-state cooling technologies. The Quantum Elastocaloric Adiabatic Refrigeration approach has the potential to materialize into a groundbreaking discovery replacing other platforms, in particular in low magnetic field and on-chip scalable applications and may have transformational impact on energy-efficient electronics, quantum computing and sensing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.