Structure Refinements of Orthorhombic (La_1-xCa_x)₂CuO₄ (x=0.05)

抄録

The structure parameters of (La_1-xCa_x)₂CuO₄ (x=0.05) with the K₂NiF₄-type structure were refined by Rietveld analysis of time-of-flight neutron powder diffraction data. This superconductor with a T_c of 24, K is orthorhombic at both room temperature and 18, K. From experimental results obtained by us and Fukuoka et al., we conclude that the relatively low T_c value for the superconductor is due to a low concentration of hole carriers introduced by Ca doping.