- Kristina Vlášková: Magnetic excitations in the cerium compounds
- 13. 1. 2016, 14:50
- lecture room F2, first floor Ke Karlovu 5
- more information
Abstract:
The CeCuAl3 compound is a member of tetragonal noncentrosymetric family of compounds, which reveals interesting electronic properties in low temperatures. These strongly correlated electron systems can exhibit single-ion crystal electric field (CEF) excitations and dispersive vibrational modes (phonons), both of similar energy scale. Usually, they are considered to be decoupled from each other. However, electron-phonon coupling can give rise to a novel and quite subtle phenomena, such as BCS type of superconductivity. It is still quite a question what happens if these CEF-phonons interactions are switch on in strongly correlated rare earth based compounds. Signature of strong correlated CEF-phonon coupling was observed in compounds like CeAl2, CePd2Al2 and CeCu2. To explain the excitation spectrum of CeAl2 was proposed CEF-phonon coupling model by Thalmeier and Fulde, which assume strong magnetoelastic coupling between lattice and orbital degrees of freedom.
CeCuAl3 crystallizes in BaNiSn3 type, which is noncetrosymetric, and Ce3+ ions form a body centered tetragonal sublattice. The inelastic neutron studies confirmed 3 magnetic excitations in the paramagnetic regime, which are consider to originate from vibron quasibound state and a modification of Thalmeier and Fulde theory for tetragonal systems was used to calculate the vibron form factor. Investigation of substituted compounds CeCuxAl1-x and (CexLa1-x)CuAl3 can help to understand the impact of CEF on the ground state of these alloys.