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 superconductivity, electronic anomaly and crystal structure at x = 1/8 in La2-xBaxCuO4. With increasing y, both the rhombic distortion of the CuO4 basal plane and the anomaly in the thermoelectric power at low temperatures become small, while T-c increases. It is concluded that the suppression of superconductivity at x = 1/8 in La2-xBaxCuO4 is due to the electronic anomaly in cooperation with the rhombic distortion of the CuO4 basal plane at low temperatures, as in the case of La1.6-xNd0.4SrxCuO4.