We report on the superconducting characteristics of the filled skutterudites LaPt4Ge12 (Tc = 8:3 K) and PrPt4Ge12 (Tc = 7:9 K) by 73Ge- nuclear quadrupole resonance (NQR) at a zero field. In PrP4Ge 12, the nuclear spin-lattice relaxation rate 73(1/T 1) has revealed a coherence peak just below Tc, indicating that the superconductivity of PrPt4Ge12 is accounted for in terms of the conventional BCS regime. The result was consistently reproduced by not only an isotropic s-wave gap model but also an anisotropic s-wave gap model with a point node. In the conventional superconductor LaPt 4Ge12, the coherence peak in 73(1/T 1) is markedly suppressed owing to some damping effect of quasiparticles. We note that the Tcs of LaPt4Ge12 and PrPt4Ge12 being higher than that of other RPt4Ge12 may be attributed to the larger density of states, not to some local anharmonic phonon modes derived from the possible rattling of R ions.
|Journal||Journal of the Physical Society of Japan|
|Publication status||Published - 2010 Jun|
- Filled skutterudite
ASJC Scopus subject areas
- Physics and Astronomy(all)