HR: 1330h
AN: V42A-0333    [PDF]
TI: Single Crystal Preparation for High Pressure Experiments in the Diamond Anvil Cell.
AU: * Aracne, C M
EM: chantel@llnl.gov
AF: Lawrence Livermore National Laboratory - Energy \& Environment, 7000 East Avenue, Livermore, CA 94550 United States
AU: Farber, D L
EM: farber2@llnl.gov
AF: Lawrence Livermore National Laboratory - Energy \& Environment, 7000 East Avenue, Livermore, CA 94550 United States
AU: Occelli, F
EM: occelli1@llnl.gov
AF: Lawrence Livermore National Laboratory - Energy \& Environment, 7000 East Avenue, Livermore, CA 94550 United States
AU: Antonangeli, D
EM: antonangeli@esrf.fr
AF: European Synchrotron Radiation Facility, BP 220, Grenoble Cedex, 38043 France
AU: Badro, J
EM: jbadro@ens-lyon.fr
AF: Laboratoire de Min\'eralogie-Cristallographie, Universit\'e Paris VI - Institut de Physique du Globe de Paris, 4, Place Jussieu, Paris Cedex 05, 75252 France
AB: Measuring the effects of pressure on geomaterials in deep Earth's P-T conditions using the diamond anvil cell (DAC) is essential for understanding the phase transition mechanisms, the mechanical properties (which derives directly from the determination of the elastic constants), and the transport properties of deep-Earth materials. To date, most DAC research has been performed with polycrystalline samples. While these are sufficient for determining orientationally averaged properties of solids ({\it i.e.} bulk modulus, P-waves and S-wave aggregate velocities, etc\ldots), single crystals offer the ability to measure a range of direction dependent properties ({\it i.e.} thermal and electrical conductivity, elasticity and plasticity, etc\ldots). Subsequent comparison of measurements on single-\ and poly-crystalline materials can, for instance, make it possible to address the effects of pressure on the elastic anisotropy and preferred orientations in deep Earth's conditions. In order to achieve pressures above 1\,Mbar, one must produce single crystal samples $\sim$25\,$\mu$m in diameter and less than 10\,$\mu$m thick. We have developed procedures to produce extremely high-quality metallic single crystals of this size from commercially available material with millimeter dimensions. Critical to the final product is the preservation of crystallinity during thinning and cutting. Our surface preparation methods include the use of selected abrasives, colloidal silica polishing and chemical etching. Samples are cut to final shape using a laser-ablation facility that can handle both conductive and insulating materials. To date, we have been successful in maintaining an extremely high degree of crystallinity and orientation in the final samples. Presently, we have analyzed cobalt and molybdenum samples with both white-light interferometry and synchrotron x-ray diffraction and are in the process of extending these methods to other metals and minerals, such as zinc, sapphire, and olivine.
DE: 3909 Elasticity and anelasticity
DE: 3924 High-pressure behavior
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
DE: 3994 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting