MRI: Acquisition of a High Field, Multi-Probe Cryogenic System for Quantum and Nano-Structured Materials Research

Johns Hopkins University, Baltimore MD

Investigators

Abstract

Technical abstract: This project will establish a high-magnetic-field, multi-probe cryogenic facility for condensed matter physics and nanostructured materials research at Johns Hopkins University (JHU). The Physical Properties Measurement System (PPMS) will provide access to four orders of magnitude in temperature (0.1 K to 1000 K) and magnetic field from 0-14 Tesla. Measurement capabilities include specific heat, electrical and thermal transport, magnetization, and magnetic susceptibility. To ensure reliable long term operations, a small helium liquefier will be an integral part of the system. The PPMS will enable a broad range of condensed matter physics and materials science: Specific heat and magnetic susceptibility measurements will be used to explore the low temperature high field phase diagram of frustrated quantum magnets and the critical properties of the corresponding phase transitions. The instrument will be used to compare static thermodynamic quantities to the complementary dynamic properties of strongly correlated metals measured through time-domain THz spectroscopy and neutron scattering. Magneto-resistance will be used to access spin transport in lateral structures and organic semiconductor nano-structures and anomalous transport in metallic thin films with arrays of micron sized holes. Magnetization measurements will be used to probe nano-magnets and superconducting nano-structures. Thermal transport measurements will probe quantum phase transitions at the insulator/superconductor boundary. Such measurements will also benchmark novel organic seminconducting materials for thermoelectric applications. Researchers throughout JHU and from our NSF-PREM partner Howard University will be able to access the instrument as will JHU seniors and graduate students through advanced laboratory courses. The instrument will also provide new opportunities for MRSEC related outreach programs. Non-technical Abstract: To understand atomic scale properties of new materials and access their utility for technical applications it is necessary to measure their physical properties under accurately controlled conditions of temperature and applied magnetic field. This project will establish a facility for such measurements to complement a wide range of materials related scientific programs at the Johns Hopkins University. The Physical Properties Measurement System (PPMS) will subject materials to temperature from 0.1 Kelvin (-459.5 F) to 1000 K (1340 F) and magnetic fields up to 14 Tesla (400,000 times the earth?s field). Under these conditions the instrument will be able to probe the specific heat, the electrical resistivity, the thermal conductivity, and the induced magnetization of materials that challenge our basic understanding of solids or present new possibilities for technical applications. The electrical resistivity of materials in high magnetic fields for example reveals intricate details of electron charge and electron spin transport through the material. Such measurements will be used to advance our understanding of organic semiconductors with potential for applications in plastic electronics. Likewise the field induced magnetization of samples reveals details about their magnetic configuration. Such measurements will be used to evaluate nano-engineered structures with potential for applications in ultra high density information storage systems. New states of matter induced by competing interactions in so-called ?frustrated magnets? and by electron interactions in so-called ?strongly correlated metals? will be explored through specific heat and magnetization measurements. Finally, thermal transport measurements will be used to probe novel thermoelectric materials that can help to address the energy challenge. The PPMS will also become an integral part of and strengthen a wide range of undergraduate, graduate, and education outreach programs at Johns Hopkins University.