Superconductivity of the compounds of LaMCuO system with K2NiF4 type structure has been studied. For the sintered compounds with MBa, Sr and Ca, the highest onset transition temperatures, Tci, estimated from resistivity measurement are about 36.9K, 43.0K and 23.5K, respectively and the highest temperatures where the resistivity vanishes, Tcf, are about 27.8K, 34.0K and 15.5K, respectively. Almost complete Meissner effect has been confirmed by low frequency ac susceptibility measurement. Crystals of the compounds with MBa and Sr have been prepared. As the result of the preliminary experiment for a crystal with Ba, it is found that Tcf of the crystal is higher than any one of the sintered specimens with MBa, while the Tci of the crystal is nearly the same as the highest one of the sintered specimens.
All Science Journal Classification (ASJC) codes
- 化學 (全部)