Scaling of the normal-state Nernst coefficient in doped Y-based high-temperature superconductors - art. no. 180515

摘要

We report experimental data on the temperature and concentration dependencies of the Nernst coefficient Q in the normal state for several series of ceramic samples of the YBa2Cu3Oy family with different kinds of deviation from stoichiometry: YBa2Cu3Oy (y=6.37-6.91), YBa2Cu3-xCoxOy (x=0-0.3), Y1-xCaxBa2Cu3Oy (x=0-0.25), and Y1-xCaxBa2-xLaxCu3Oy (x=0-0.5), as well as their comparative qualitative analysis with respect to the other transport coefficients' behavior. The Nernst coefficient is very small and positive at T=300 K for all the investigated samples, and in the case of a small absolute value Q becomes negative at low temperatures (T<150 K). Deviations from stoichiometry influence the absolute value of Q, such as that of other transport coefficients, i.e., the Q(T=300 K) value increases in the case of single substitutions (YBa2Cu3Oy and YBa2Cu3-xCoxOy) and changes insignificantly for double-substituted systems (Y1-xCaxBa2Cu3Oy and Y1-xCaxBa2-xLaxCu3Oy). [References: 16]