Investigation of thermoelectric power with modification of two band model with linear T term for superconductors and thermal conductivity study of Se added YBCO samples

摘要

In this study, the electrical and thermal transport properties such as thermoelectric power and thermal conductivity of the Se added YBCO system was investigated. The samples fabricated under different heat treatment conditions exhibited the T_c value between 90.1 K and 80.6 K. Positive thermoelectric power for all the samples was obtained over all measurement temperature range which indicates the hole type conductivity. Thermoelectric power data was analyzed by replacing term (T-T') by T in "Modified two band model with linear T-term" which is good agreement with experimental TEP data for all the samples. f obtained by fitting" corresponds to a temperature close to T_o obtained from resistivity measurement. Temperature dependence of thermal conductivity of the samples showed small peak with broad maximum just below T_c. Thermal conductivity of the samples prepared was analyzed by the lattice thermal conductivity component by "The modified Callaway model" and the electronic component by "Wiedemann-Franz law".