Browsing by Author "Bao, Z. X."

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Electrical properties, equations of state and phase transition in solid C60 at high pressure
(2000) Bao, Z. X.; Schmidt, V. Hugo; Dalal, N. S.; Tu, Chi-Shun; Pinto, Nicholas J.; Liu, C. X.; Li, X. L.; Zhu, Dao-Ben
Electrical properties and equations of state in solid C60 at room temperature and high pressure have been studied in a diamond anvil cell using capacitance and resistance measurements and a piston-cylinder type device using P-V measurements, respectively. Experimental results by capacitance and P-V measurements indicate that solid C60 also undergoes a phase transition at room temperature and a lower pressure, about 2GPa. The phase transition may be from a face-centered-cubic to a simple-cubic structure.
Ion beam induced adhesion in Al/diamond bilayer
(1991-07-01) Saleh, Adli A.; Smith, R. J.; Shutthanandan, Vaithiyalingam; Bao, Z. X.; Schmidt, V. Hugo
Diamond anvil cells are often used to study phase transitions in materials under high pressure. To probe these transitions, electrodes with low resistance and good adhesion properties are desired. Such electrodes were obtained using ion beam mixing techniques. The diamond anvil was first irradiated with a 100 keV Ar+ beam with an ion dose of 1016 ions/cm 2. Resistance measurements of the irradiated area indicated that ion beam damage induced a low-resistance phase of carbon. A thin Al film (≈ 500 Å) was then deposited on the diamond anvil followed by Ar+ irradiation. The deposition and irradiation processes were repeated, followed by resistance measurements after each irradiation. The measurements indicate the formation of a low resistance layer (R ≈ 10gW). A qualitative test of adhesion was performed by scratching the formed layer with the resistance probes. The resistance of the electrode showed an acceptably small increase as a function of scraping. These results can be understood on the basis of recoil mixing in the Al/diamond system.
Phase Transitions in KH2PO4 and RbH2PO4 to 14 GPa Observed by Capacitance Change in a Diamond Anvil Cell
(1991) Bao, Z. X.; Schmidt, V. Hugo; Howell, Francis L.
Phase transitions in KH2PO4(KDP) and RbH2PO4 (RDP) at room temperature for pressures up to 14 GPa have been determined by means of capacitance measurements using a diamond anvil cell.Phase transitions occur in KDP near 2.5 and 7.0 GPa. In RDP, a transition was detected near 5.4 GPa.
Phase transitions in tris-sarcosine calcium chloride (TSCC) to 14 GPa
(1993) Bao, Z. X.; Schmidt, V. Hugo; Howell, Francis L.
The capacitance of samples of tris-sarcosine calcium chloride (TSCC) has been measured at room temperature at pressures up to 14 GPa. A diamond anvil cell was employed to control the pressure. Experimental results indicate that TSCC undergoes two phase transitions, near 1.3 GPa and 4.1 GPa.