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Cryorefrigerator System: We have an operational cryocooling apparatus configured to perform several low temperature measurements. It currently is capable of measuring electrical resistance in both the 4-wire probe method and the Van der Pauw style method. This device is currently undergoing upgrades to allow for thermoelectric measurements and high pressure transport measurements. It is a Cryomech model helium pump cryocooler with 10 pin hermetic connectors and a dedicated vacuum system capable of better than 10^-5 torr pressures inside when sealed. The sample and temperature electrical probes are accessed through one of the hermetic connectors, with two thermocouple connections available through a modified pressure relief valve port on the front of the cryostat. The cooler is capable of reaching 20-40 K after two hours of operation.
High Pressure Thermal and Electrical Cell: A more recent addition to our laboratory facilities is an opposed anvil tungsten carbide bridgman cell. This cell uses the split gasket design with a 6 mm culet and 6 mm annular pyrophyllite outer gasket with a 2 mm disk steatite inner gasket for a pressure medium. This cell was recently commissioned and has been tested to be capable of 18 GPa routinely. The cell pressure is applied through use of a Carver model hydraulic press. This press is coupled to a pressure transducer for easy computer interfacing and has been calibrated using Bi, Sn, and Pb electrical transitions.
Multi-purpose Measurement System: One of the major challenges in being able to measure transport properties of materials is being able to utilize the same equipment for the measurements. To address this, the equipment used for the high pressure thermal and electrical characterizations and the cryostat characterizations was developed in such a way as to allow easy reconfiguation for the type of measurements being performed. This group of equipment consists of a Lakeshore model 370 AC resistance bridge, two Keithley model 2000 digital multimeters, one Keithley model sourcemeter, a pressure transducer, and one homebuilt thermocouple amplifier.
Sensitive Sample Preparation Center: Currently under testing conditions, we are developing a glove box system for the preparation of sensitive samples. This glove box is equipped with a CCD coupled microscope and argon tank gas for displacing air. It is also connected to a vacuum line to facilitate water/oxygen removal from the interior of the glove box. It is anticipated that this center will be fully operational in the near future.
Physical Property Measurement System: We also have available a Quantum Design Physical Property Measurement system equipped with the Resistivity, AC Transport, AC Susceptability, Helium-3, and Heat Capacity Options. We are looking into obtaining the Thermal Transport Option in the near future.
High Pressure Cells: Our group has access to many different types of pressurization cells including Merrill-Bassett and Mao-Bell type diamond anvil cells, Wide angle diamond anvil cells in both steel and Cu-Be, and Sapphire Piston Cells.
As members of the High Pressure Science and Engineering Center, our staff also has access to:
Sample Synthesis Facilities, High Pressure and Variable Temperature X-Ray Diffraction, High and Ambient Pressure Raman and Infrared Spectroscopy, and High Pressure Optical Spectrocopy (Transmission and Reflection).
In addition, the HiPSEC group is currently a part owner (25%) of sector 16 (HPCAT) at the Advance Photon Source at Argonne National Laboratory, with additional connections at Brookhaven National Laboratory and the Stanford Synchrotron Radiation Laboratory. Through these partnerships, we have access to revolutionary x-ray techniques including:
High Pressure Powder and Single Crystal Diffraction (Energy and Angular Dispersive), Nuclear Forward and Resonant Inelastic X-ray Scattering, X-Ray Raman Studies, and Cryogenic X-Ray Diffraction.
©2006 M. Jacobsen