LOW-TEMPERATURE ELECTRONIC SPECIFIC-HEAT IN LA2-XSRXCU1-YZNYO4

Electronic specific heat C-el at T less than or equal to 10 K was stud ied on La2-xSrx Cu1-yZn3O4 below and above the critical Zn-content y(c ) at which the superconductivity disappears. The specific heat C-el of non-doped superconducting samples exhibits a T-2-dependence, peculiar to a d-wave superconductor. The T-linear component of C-el appears in Zn-doped superconducting samples, and its coefficient gamma increases markedly with Zn content. In samples with various Zn contents, the re lation between T-c/T-cy=0 and gamma/gamma(y>yc) can be understood in t erms of strong impurity scattering in a d-wave superconductor.