Impurity scattering effects on the low-temperature specific heat of d-wave superconductors

Abstract

Recently, impurity scattering effects on quasiparticles in d-wave superconductors have attracted much attention. In particular, the thermodynamic properties in magnetic fields are of interest. We have measured the low-temperature specific heat C(T,H) of La1.78Sr0.22Cu1-xNixO4. The impurity scattering effects on C(T,H) of cuprate superconductors were clearly observed and are compared with the theory of d-wave superconductivity. It is found that impurity scattering leads to the relation gamma(H) = gamma(o)[1 + D(H/H-c2)ln(H-c2/H)] in small magnetic fields. Surprisingly, the sealing of C(T,H) is broken down by impurity scattering.