Electrical and thermal transport properties of EuBa₂(Cu _1-xMn_x)₃O_7-δ

In this communication, we present the measurements of electrical resistivity (ρ), thermal conductivity (κ), thermopower (S), and specific heat (C_P) on Mn doped compounds EuBa₂(Cu _1-xMn_x)₃O_7-δ for 0≤x≤0.02. The transition temperature T_C and the upper critical field H_C2(0) in this series of compounds are found to decrease quasi-linearly as the Mn concentration increases. All the currently investigated samples show a hump in thermal conductivity below their transition temperatures. Thermopower measurements exhibit an electron-like behaviour for pure samples; however, a hole-like behaviour is seen in all the doped samples. A small jump in specific heat is observed in the pure samples. It is seen that replacing 0.5% Cu by Mn has little effect on the transition temperature, but there is a nearly twofold suppression in the C_P jump for this sample. These results demonstrate that the impurities are being incorporated as a whole and not as a cluster.