Thermal conductivity and thermo-power of ( and ) bulk superconductors

In this paper, we present temperature dependent electrical conductivity ρ ( T ) , thermal conductivity κ ( T ) and thermoelectric power S ( T ) for co-doped superconducting compounds Y 0.95Pr0.5Ba2(Cu1−xMx)3O7−δ(M=Fe,Mn,Zn and Ni). The XRD patterns confirm that all the samples are single phased. Pristine Y Ba2Cu3O7−δ depicts a pronounced hump-like structure in κ ( T ) below its transition temperature. With Pr-doping, a reduction in the peak height of the hump is observed. It is found that the hump structure is further suppressed with transition metal co-doping, and is viewed in terms of the phonon scattering with defect structure, electrons and phonons. S ( T ) data depicting a sign reversal with co-doping, has been analyzed in the framework of a narrow band model.