Dissipation in Non-Kramers Doublet of PrMg3
Abstract
The low-temperature ultrasonic dispersion in the transverse (C11-C12)/2 mode of PrMg3 with the non-Kramers-doublet ground state has been investigated in temperatures down to 20 mK. The dispersion is caused by a thermally activated motions characterized by an Arrhenius-type relaxation time of τ=τ0\exp(E/kBT) with low activation energy, E = 500 mK, and slow attempt time, τ0=8.5× 10-10 s. The coupling of the electric quadrupoles of the non-Kramers-doublet ground state to transverse lattice vibrations leads to a vibronic ground state with dissipation. The vibronic state in PrMg3 releases the entropy of kB\ln 2 with lowering temperature across the activation energy. A Kondo-like singlet state due to the binding of the non-Kramers doublet to the lattice vibrations appears at low temperatures far below the activation energy.
- Publication:
-
Journal of the Physical Society of Japan
- Pub Date:
- February 2012
- DOI:
- 10.1143/JPSJ.81.023710
- Bibcode:
- 2012JPSJ...81b3710A