The synthesis condition and its influence on Tc in Mn doped La1.85Sr0.15CuO4

The detailed synthesis condition of Mn doped La1.85Sr0.15CuO4 superconductors and the effects of the synthesis condition on the onset critical transition temperature are discussed. We address that the traditional solid-state reaction method tends to result in impurity phases which needs to be improved. These minor impurity phases are harmful to the superconductivity. The improvement is effective in synthesizing Mn doped samples without impurities. On the contrary to the cases of Zn or Ni doping, the introduction of Mn in La1.85Sr0.15CuO4 superconductors does not lead to a rapid decrease of the Tc value. The onset critical transition temperature remains nearly unchanged in Mn doped samples. The investigation on this issue would contribute to the final solution of the pairing mechanisms in cuprate superconductors.