1.
J Phys Condens Matter
; 25(29): 296002, 2013 Jul 24.
Artigo
em Inglês
| MEDLINE
| ID: mdl-23803419
RESUMO
We have investigated quadrupole effects in tetragonal crystals of PrCu2Si2 and DyCu2Si2 by means of low-temperature ultrasonic measurements. The elastic constant C44 of PrCu2Si2 exhibits pronounced softening below 70 K down to a Néel temperature TN = 20 K, which is described in terms of a quadrupole susceptibility for a Γ5 doublet ground state and a Γ3 singlet first excited state located at 15.6 K in the crystalline electric field scheme. The C44 and C66 of DyCu2Si2 also show softening below 70 K down to TN1 = 9.7 K. A low-lying pseudo-sextet state consisting of three Kramers doublets of Γ6â2Γ7 brings about softening of C44 and C66 in DyCu2Si2.