Crystal structure and superconducting properties of KSr2Nb3O10

We performed X-ray diffraction (XRD) and DC magnetic susceptibility measurements to elucidate the crystal structure and superconducting properties of KSr₂Nb₃O₁₀. From the diffraction pattern indexing, it was found that KSr₂Nb₃O₁₀ crystallizes with monoclinic symmetry, space group P2₁/m(11). We succeeded in preparing high temperature (HT) and low temperature (LT) phases of KSr₂Nb₃O₁₀ powder samples synthesized by a conventional solid state reaction and an ion-exchange reaction, respectively. Superconductivity was observed at 4 K by Li intercalation and it was found that the superconducting volume fraction of the LT phase (~ 1.4%) is clearly larger than that of the HT phase (0.07%).