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

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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.