Aggregate and single-crystalline elasticity of hcp cobalt at high pressure
- European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex (France)
- Institut de Mineralogie et de Physique des Milieux Condenses, UMR CNRS 7590, Institut de Physique du Globe de Paris, Universite Paris 6, 4 Place Jussieu, 75252 Paris Cedex 05 (France)
- Earth Science Division, Energy and Environment Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba (Japan)
The longitudinal acoustic phonon dispersion of polycrystalline cobalt was determined by inelastic x-ray scattering up to 99 GPa, throughout the entire stability field of the hcp phase. The obtained aggregate compressional and shear sound velocities are compared with recent single crystal results, impulsive stimulated light scattering and ambient pressure ultrasonic measurements, as well as first principle calculations. We observe a linear evolution of the sound velocities with density up to 75 GPa. In this pressure range, the aggregate elastic properties of the polycrystalline sample are reproduced within 3% by a Voigt-Reuss-Hill average of the single crystal C{sub ij}. Above 75 GPa both aggregate velocities show a softening. Our comparative analysis of single-crystalline and polycrystalline results points towards a magnetic origin of the anomaly.
- OSTI ID:
- 20719595
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 13 Vol. 72; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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