CORRELATION BETWEEN SUPERCONDUCTIVITY, ELECTRONIC-STATE AND CRYSTAL-STRUCTURE IN LA2-Y-XBIYBAXCUO4

The effects of substitution of Bi for La have been investigated in La2 -y-xBiyBaxCuO4 (x = 1/8), to clarify the correlation between the super conductivity, electronic anomaly and crystal structure at x = 1/8 in L a2-xBaxCuO4. With increasing y, both the rhombic distortion of the CuO 4 basal plane and the anomaly in the thermoelectric power at low tempe ratures become small, while T-c increases. It is concluded that the su ppression of superconductivity at x = 1/8 in La2-xBaxCuO4 is due to th e electronic anomaly in cooperation with the rhombic distortion of the CuO4 basal plane at low temperatures, as in the case of La1.6-xNd0.4S rxCuO4.