Dresden 2003 – wissenschaftliches Programm
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SYEC: Materials under extreme conditions
SYEC 3: Extreme Conditions (Poster Session)
SYEC 3.7: Poster
Mittwoch, 26. März 2003, 13:00–19:00, P2a
High-pressure/high-temperature structural studies of cerium: Semi-empirical fit equation for the isostructural γ-α-transition — •Andreas Schiwek1, Felix Porsch2, Ulrich Ponkratz1, Christian Lathe3, and Wilfried B. Holzapfel1 — 1Department Physik der Universität Paderborn, D-33095 Paderborn, Germany — 2Mineralogisch-Petrologisches Institut der Universität Bonn, D-53115 Bonn, Germany — 32 GeoForschungsZentrum Potsdam, Telegraphenberg , D-14473 Potsdam, Germany
PV-relations around the critical point of the γ-α-phase transition in Cerium were determined from experiments using the energy dispersive X-ray - diffraction technique at the large volume press MAX 80 at HASYLAB / DESY. A new semi-empirical model suitable for a description of this f-electron delocalisation transition is parametrically fitted to various isotherms.
Furthermore the α-є-phase boundary was studied experimentally to complete the phase diagram in the accessible region of pressure and temperature [1]. Other recent results are included [2,3,4] for the new phase diagram.
[1] A. Schiwek, F.Porsch, W.B. Holzapfel, High Press. Res. 22(2), 407-10 (2002).
[2] B. Sitaud, J. Péré, Th. Thévenin, High Press. Res. 12, 175-86 (1994).
[3] M.I. McMahon and R.J. Nelmes, Phys. Rev. Lett. 78, 3884-87 (1997).
[4] Y.K. Vohra, S.L. Beaver, J.Akella, Ch.A. Ruddle, S.T. Weir, J. Appl. Phys. 85, 2451-53 (1999).