We have measured the specific heat C of a polycrystalline sample of the non-cuprate superconductor Ba0.6K0.4BiO3 (Tc ≈ 27K) from T = 1.8K down to T = 0.1K. The data could be fitted accurately to the expression C = AT-2 + αTn + βT3 where n = 0.53 ± 0.10. The nuclear term (AT-2) is attributed to the presence of a crystalline electric field gradient on the Bi nuclei. The residual specific heat term (αTn) has also been observed in the low temperature specific heat of several cuprate high-Tc superconductors (0.3 ≤ n ≤ 1) suggesting a possible common origin in all of these systems.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering