We present the results of the superconducting properties of R 3Ti4Sn13 (R = La, Sr, and Ca; T = Co, Rh, and Ir) with quasi skutterudite structure by means of magnetic susceptibility, electrical resistivity, and specific heat measurements. It is shown that the superconductivity is of conventional s-wave type and lies in the extremely strong-coupling regime. Electron-phonon coupling constants λep were estimated to be almost 1 for R3Ti4Sn13, respectively. The result can be categorized as a strong-coupling superconductor; this categorization is in good agreement with the results of specific heat measurements. The λep and the electronic density of states at the Fermi level (N(EF)) increases with the superconducting transition temperature. However, superconducting transition temperature of Co-compound cannot be explained by the difference of N(EF). From these results, we concluded that Tc of R3Ti4Sn13 can be described by the strength of the λep.
- Specific heat
- Strong-coupling superconductor
ASJC Scopus subject areas
- Physics and Astronomy(all)