Structural Evolution Induced by Changing Hole Carrier Density in (Hg,Tl)2Ba2(Cax,Y1-x)Cu2Oy

The effect of Ca substitution for Y on the crystal structure was investigated by means of powder x-ray Rietveld refinement for high-pressure-formed (Hg,Tl)2Ba2(Cax,Y1-x)Cu2Oy (x=0.1, 0.2, 0.4 and 0.6) samples. A selected sample, (Hg,Tl)2Ba2(Ca0.2,Y0 8)Cu2Oy, was annealed in Ar gas at 300 °C for 0.5 hr or 12 hr, and at 400 °C for 36 hr. The crystal structures of the annealed samples were also determined by powder x-ray Rietveld refinement. A comparison of the variation tendency for several particular inter-planar distances was made for these substituted and post-annealed samples.