MRI: Acquisition of a Cryogen-Free Physical Properties Measurement System (PPMS DynaCool)

在制造下一代超级计算机或先进通信工具的过程中，当今技术面临的许多紧迫挑战都可以通过有针对性地控制材料功能（例如，电、磁或热性能）来解决。在精确控制条件下测量材料的物理性质对于理解新材料的原子尺度性质和获取其技术应用的实用性起着关键作用。无低温物理性能测量系统（PPMS DynaCool）的获得使杜克大学的研究人员能够以高样品吞吐量测量各种材料的性能，而不需要任何液体低温。这台最先进的仪器不仅可以为学生和博士后提供研究培训，还可以为本科生和研究生提供工程和科学实验课程，以及杜克大学已经为高中生、高中教师和本科生提供的广泛的材料研究教育推广项目。该仪器也可供更广泛的三角研究社区使用，进一步实现发展更多样化的科学工作队伍的目标。----------物理性质测量系统（PPMS）是杜克大学的重要补充？这将极大地影响科学探究的许多领域，从量子磁性、拓扑效应和紧急临界现象的基础研究，到纳米磁铁和超导纳米结构中的电输运，到设计和评估分子、纳米尺度和宏观材料，再到碳纳米管和石墨烯中的电子相关性研究。表征新型有机半导体和混合材料的能源应用，合成和表征高温超导体。PPMS配备了一个集成的传导冷却超导特斯拉磁体。该系统提供无缝的温度转换，能够在45分钟内将样品室从室温冷却到1.8 K并稳定到优于0.001 K。稀释冰箱插入提供了进行低至50 mK测量的能力，这对于探测材料中的量子力学现象至关重要。样品室可容纳各种测量插入件，所有这些插入件都允许在全范围的磁场和温度下在计算机控制下全自动数据采集。一个多功能探头适应自定义实验，和一个水平样品旋转器允许磁电阻测量作为一个函数的样品方向相对于磁场。该系统能够测量电阻率、导热系数、比热、霍尔效应和其他热电性能，以及磁化率和磁化强度。该系统的无低温特性确保了设备的经济高效和可靠的长期运行，使其能够适应它将服务的大型用户群。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many of the pressing challenges that technologies are facing today in moving toward manufacturing the next generation of supercomputers or advanced communication tools can be solved with the targeted control of materials functionalities (e.g., electrical, magnetic or thermal properties). Measuring physical properties of materials under accurately controlled conditions plays a key role in understanding atomic scale properties of the new materials and accessing their utility for technical applications. The acquisition of the cryogen-free Physical Properties Measurement System (PPMS DynaCool) empowers researchers at Duke University to measure a wide range of materials properties with a high sample-throughput rate, without the need for any liquid cryogens. This state-of-the-art instrument not only enables the research training of students and postdoctoral associates, but it also benefits undergraduate and graduate engineering and science laboratory courses, and the extensive education outreach programs focused on materials research that are already in place at Duke for high school students, high school teachers, and undergraduates. This instrument is also available to the broader Research Triangle community, furthering the goal of developing a more diverse scientific workforce.----------The Physical Properties Measurement System (PPMS) is an important addition to Duke University?s materials research infrastructure and will greatly impact many areas of scientific inquiry, ranging from fundamental studies of quantum magnetism, topological effects and emergent critical phenomena, to electrical transport in nanomagnets and superconducting nanostructures, to designing and evaluating molecular, nanoscale and macroscopic materials, to studies of electronic correlations in carbon nanotubes and graphene, to characterization of novel organic semiconductor and hybrid materials for energy applications, to synthesis and characterization of high-temperature superconductors. The PPMS is equipped with an integrated conduction-cooled superconducting 14 Tesla magnet. This system provides seamless temperature transition and is capable of cooling the sample chamber from room temperature to 1.8 K and stabilizing to better than 0.001 K in under 45 minutes. A dilution refrigerator insert provides the capability to conduct measurements down to 50 mK, essential for probing quantum mechanical phenomena in materials. The sample chamber accommodates a wide range of measurement inserts, all of which allow fully automated data acquisition under computer control over the full range of magnetic field and temperature. A multi-function probe accommodates custom experiments, and a horizontal sample rotator allows magnetoresistance measurements as a function of sample orientation relative to magnetic field. This system provides the capability to measure electrical resistivity, thermal conductivity, specific heat, Hall Effect, and other thermoelectric properties, as well as susceptibility and magnetization. The cryogen-free feature of this system ensures cost-effective and reliable long-term operation of the equipment, enabling it to accommodate the large user base it will serve.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.