Development of a High Magnetic Field Pulsed Nuclear Magnetic Resonance (NMR) System for Materials Research

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Partial support is provided to the University of California- Los Angeles for the development of a novel, compact pulsed nuclear magnetic resonance (NMR) instrument for research in condensed matter science. The new instrument will operate over a broad range of steady magnetic fields that extends up to the highest available. The main parts of the system consist of: (1) A compact, portable, medium-power pulsed NMR spectrometer with frequency coverage up to 2 GHz, (2) a low- helium consumption 9-T superconducting solenoid for experiments at UCLA, and (3) a wide variety of probes to accommodate different magnets and experimental conditions of temperature, NMR frequency, and sample alignment. Experiments below 9 T will be conducted at UCLA. For the higher fields (up to 45 T), the spectrometer will be transported to the laboratories at other institutions that house the high-field magnets. Since many of these magnets do not have the field stability and homogeneity necessary for NMR measurements, correction coils will be added to the probes to overcome these difficulties. The NMR research topics to be investigated with the system include the static and dynamic properties of spin density waves, vortex pinning and dynamics in superconductors, and nanocrystal compounds. A secondary use by UCLA investigators of the 9 T magnet that involves very little liquid helium consumption will be thermal, magnetic and frequency dependent electrical transport investigations of correlated electron systems. In these applications, the field at the sample will be swept by maintaining the magnet in the persistent mode and physically lowering it to move its fringing field past the sample. Aside from studies at UCLA, collaborations will be established with other investigators to use the NMR spectrometer at various high field laboratories.