Yongrong Shen

Characteristics of silicone fluid as a pressure transmitting medium in diamond anvil cells

The properties of a silicone fluid with initial viscosity of 1 cst as a pressure transmitting medium for diamond anvil cells have been determined by ruby R1 line broadening and R1-R2 separation measurements to 64 GPa at ambient temperature. By these criteria, the silicone fluid is as good a pressure medium as a 4:1 methanol:ethanol mixture at low pressures to about 20 GPa, and is better than the mixture at higher pressures. Although argon media are better than the silicone at pressures to 30 GPa, this silicone behaves as well as argon at higher pressures. Furthermore, the silicone is easier to load than argon and is almost chemically inert.

High pressure Raman spectroscopic study of structural polymorphismin cyclohexane

We have performed a Raman spectroscopic study of cyclohexane at high pressures up to 40GPa at ambient temperature and present evidence for one or two new phases of cyclohexane which appear around 10 and between 25 and 37GPa. The R1 and R2 lines of a ruby in the cyclohexane sample were well-resolved to our highest pressure, and the sample was highly transparent. Because cyclohexane is nonpolar, relatively inert, and a liquid at room temperature, it is an excellent and easy-to-use pressure medium, especially for reactive materials. At 40GPa, we heated the sample to 200 °C for several hours and then performed Raman measurements while decreasing pressure at ambient temperature. The material remained in its original liquid form demonstrating that the molecule is remarkably resilient.

Pressure induced structural phase transition inAgSbTe2

We report a novel high pressure structural sequence for the functionally graded thermoelectric, narrow band gap semiconductor AgSbTe

High-pressure studies of cyclohexane to 40 GPa.

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Structural behavior of non-oxide perovskite superconductor MgCNi3 at pressures up to 32 GPa

, using angle dispersive x-ray diffraction in a diamond anvil cell with synchrotron radiation at room temperature. The compound undergoes a B1 to B2 transition; the transition proceeds through an intermediate amorphous phase found between 17-26 GPa that is quenchable down to ambient conditions. The pressure induced structural transition observed in this compound is the first of its type reported in this ternary cubic family, and it is new for the B1-B2 transition pathway reported to date. Density Functional Theory (DFT) calculations performed for the B1 and B2 phases are in good agreement with the experimental results.