Acquisition of a High Field Low Temperature Cryo-system for Neutron Scattering

9704257布罗霍姆该合同为购买用于中子散射实验的12特斯拉超导磁体和稀释制冷机的低温系统提供支持。该仪器将安装在马里兰州盖瑟斯堡的国家标准与技术研究所反应堆辐射部。约翰霍普金斯大学、普林斯顿大学和马里兰大学学院公园的调查人员将分享这份报告。研究人员将使用这台仪器进行NSF资助的对凝聚态物理基本感兴趣的磁性和超导材料的研究。这些材料包括：低维反铁磁体，其中量子诱导无序提供了新的合作现象；有机导体(贝克加德盐)，它显示了自旋密度波态之间一系列不寻常的场诱导相变；以及重费米子材料，其中局部磁矩和传导电子之间的相互作用产生了新的磁态。此外，还介绍了高T_c超导体中涡旋晶格的高场研究，以及在高T_c材料和一类新的四元金属间化合物中磁性和超导共存的探索。在所有这些系统中，大磁场的应用可以明显改变它们的行为，特别是它们的磁关联和激发。通过用非弹性中子散射直接探测这些效应，将有可能极大地扩展对这些材料的理解。该仪器将通过NIST的中子散射用户计划向其他研究人员提供。因此，它将成为整个美国中子散射界的重要世界级资源。%该合同为购买用于中子散射实验的12特斯拉超导磁体和稀释制冷机的低温系统提供支持。该仪器将安装在马里兰州盖瑟斯堡的国家标准与技术研究所反应堆辐射部。约翰·霍普金斯大学、普林斯顿大学和马里拉德大学帕克学院的研究人员将分享这份报告。研究人员将使用这台仪器进行NSF资助的对凝聚态物理基本感兴趣的磁性和超导材料的研究。这些材料包括：低维反铁磁体，其中量子诱导无序提供了新的合作现象；有机导体(贝克加德盐)，它显示了自旋密度波态之间一系列不寻常的场诱导相变；以及重费米子材料，其中局部磁矩和传导电子之间的相互作用产生了新的磁态。此外，还介绍了高T_c超导体中涡旋晶格的高场研究，以及在高T_c材料和一类新的四元金属间化合物中磁性和超导共存的探索。在所有这些系统中，大磁场的应用可以明显改变它们的行为，特别是它们的磁关联和激发。通过用非弹性中子散射直接探测这些效应，将有可能极大地扩展对这些材料的理解。该仪器将通过NIST的中子散射用户计划向其他研究人员提供。因此，它将成为整个美国中子散射界的重要世界级资源。***

9704257 Broholm This award provides support for the acquisition of a cryo- system consisting of a 12 Tesla superconducting magnet and a dilution refrigerator for use in neutron scattering experiments. The instrument will be located at the Reactor Radiation Division of the National Institute of Standards and Technology in Gaithersburg, MD. It will be shared by investigators at Johns Hopkins University, Princeton University, and the University of Maryland, College Park. Researchers will use this instrument for NSF funded research of magnetic and superconducting materials of fundamental interest in condensed matter physics. These include: low-dimensional antiferromagnets where quantum-induced disorder gives novel cooperative phenomena, orgranic conductors (Bechgard salts) that display a cascade of unusual field-induced phase transitions between spin-density wave states, and heavy fermion materials where interactions between local magnetic moments and conduction electrons yield novel magnetic states. Also featured are high-field studies of the vortex lattice in high- Tc superconductors, and exploration of the coexistence of magnetism and superconductivity in the high-Tc materials and a new class of quaternary intermetallic compounds. All of these are systems where the application of a large magnetic field can proufoundly alter their behavior, particularly their magnetic correlations and excitations. By probing these effects directly with inelastic neutron scattering, it will be possible to greatly extend the understanding of these materials. The instrument will be made available to other researchers through the neutron scattering users programs at NIST. It will therefore become an important world-class resource for the entire United States neutron scattering community. %%% This award provides support for the acquisition of a cryo- system consisting of a 12 Tesla superconducting magnet and a dilution refrigerator for use in neutron scattering experiments. The instrument will be located at the Reactor Radiation Division of the National Institute of Standards and Technology in Gaithersburg, MD. It will be shared by investigators at Johns Hopkins University, Princeton University, and the University of Marylald, College Park. Researchers will use this instrument for NSF funded research of magnetic and superconducting materials of fundamental interest in condensed matter physics. These include: low-dimensional antiferromagnets where quantum-induced disorder gives novel cooperative phenomena, orgranic conductors (Bechgard salts) that display a cascade of unusual field-induced phase transitions between spin-density wave states, and heavy fermion materials where interactions between local magnetic moments and conduction electrons yield novel magnetic states. Also featured are high-field studies of the vortex lattice in high- Tc superconductors, and exploration of the coexistence of magnetism and superconductivity in the high-Tc materials and a new class of quaternary intermetallic compounds. All of these are systems where the application of a large magnetic field can proufoundly alter their behavior, particularly their magnetic correlations and excitations. By probing these effects directly with inelastic neutron scattering, it will be possible to greatly extend the understanding of these materials. The instrument will be made available to other researchers through the neutron scattering users programs at NIST. It will therefore become an important world-class resource for the entire United States neutron scattering community. ***