Europhys. Lett.
Volume 61, Number 6, March 2003
Page(s) 783 - 789
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 March 2003
DOI: 10.1209/epl/i2003-00302-7
Europhys. Lett., 61 (6) , pp. 783-789 (2003)

Phase transition mechanisms in lanthanide elemental crystals

V. P. Dmitriev, A. Yu. Kuznetsov, D. Machon, H.-P. Weber and P. Tolédano

Group "Structure of Materials under Extreme Conditions", SNBL/ESRF BP220, 38043 Grenoble Cedex, France

(Received 29 July 2002; accepted in final form 6 January 2003)

A unifying theoretical description is given of the phase transition mechanisms occurring in lanthanide elemental crystals. The hcp-9R-dhcp-fcc sequence of reconstructive phase transitions is interpreted in terms of crossover between displacive and reordering mechanisms. The distorted fcc, monoclinic, $\alpha$-U-type and bct high-pressure phases can be depicted by purely displacive mechanisms, the low symmetry of these phases resulting from the non-spherical shape of the electronic shells induced by the delocalization of the f-electrons.

64.70.Kb - Solid-solid transitions.
81.30.Kf - Martensitic transformations.

© EDP Sciences 2003