Search for New Superconductors by Soft-Chemical Techniques

Our Recent Works on the Search for New Superconductors Using Soft-Chemical Techniques Are Reviewed. We Have Found New Mg-Intercalated Superconductors of MgxZrNCl and MgxHFNCl with Tc ~ 13 K and 25 K, Respectively. Moreover, we Have Succeeded in Preparing Bulk Samples of Hole-Doped (La,Ca)2CuO4 with the Nd2CuO4-Type, Namely, the so-Called T’-Type Structure by Reduction of (La,Ca)2CuO4 with the K2NiF4-Type, Namely, the so-Called T-Type Structure Using CaH2 at a Temperature as Low as 300°C and Subsequent Oxidation. This Result Is in Contrast with the Synthesis of (La,Ca)2CuO4 with the K2NiF4-Type Structure by the Conventional Solid-State Reaction Method at a Temperature as High as ~1000°C.