SPECIFIC-HEAT OF SINGLE-CRYSTAL BA0.6K0.4BIO3 AT LOW-TEMPERATURES

We report measurements of the specific heat of a large single crystal of Ba0.6K0.4BiO3 taken between 0.4K and 4.2K. Upon subtracting the pho non and nuclear quadrupole contributions, the residual specific heat i s found to have a T-n temperature dependence with n approximate to 0.8 . A similar low-power temperature dependence has been observed in the low temperature specific heat of the cuprate high-T-c superconductors and suggests a common origin for this term in both systems, possibly a rising from localization of the quasiparticles at low temperatures.