酸化物超伝導体の合成と評価 電気化学的手法による層状ニオブ酸化物ＡＣａ２Ｎｂ３Ｏ１０（Ａ＝Ｋ，Ｒｂ，Ｃｓ）へのＬｉインターカレーション

Abstract

We prepared Li-intercalated layered niobium oxide LixACa2Nb3O10(A=K, Rb, Cs) by an electrochemical technique. The host compounds ACa2Nb3O10 were synthesized by a solid state reaction method at 850-1150°C for 10-12h. Each of the cyclic voltammograms of these compounds had one cathodic peak at--3V, indicating that the Li-intercaration occurred at this voltage. All of the intercalated compounds LixACa2Nb3O10 (A=K, Rb, Cs) showed superconductivity at 4-5K, and their x-ray diffraction pattern remained almost unchanged in spite of the Li-intercalation. For LixRbCa2Nb3O10, no superconductivity appeared up to x = 0.17, for x=0.34 and 0.46 Tc (determined as the onset of the Missner effect) was constant at 4 K, and for x = 0.62 Tc decreased slightly to 3K.