Lattice dynamics of the lanthanides: Samarium at high pressureH. Olijnyk and A. P. Jephcoat
Department of Earth Sciences, University of Oxford - Oxford OX1 3PR, UK
received 4 August 2004; accepted in final form 19 November 2004
published online 24 December 2004
Sm was studied by Raman spectroscopy at pressures up to 20 . The Raman-active phonon modes, both of the Sm-type phase and the dhcp phase, show a frequency decrease as pressure increases. There is evidence that the entire structural sequence - under pressure for the individual regular lanthanides is associated with softening of certain acoustic and optical-phonon modes as well as elastic anomalies. Comparison is made to corresponding transitions between close-packed lattices in other metals and possible relations to the lanthanide's electronic structure are addressed.
62.50.+p - High-pressure and shock wave effects in solids and liquids.
64.70.Kb - Solid-solid transitions.
63.20.-e - Phonons in crystal lattices.
© EDP Sciences 2005