A comparison of the structural evolution induced by changing the hole-doping level in three series (Hg, Tl)-22(n - 1)n (n = 2,3) samples

摘要

Three series of (Hg, Tl)-22(n - 1)n (n = 2, 3) samples were synthesized by a high-pressure technique. One series of samples was prepared by substituting Y for the Ca site in (Hg_(0.7), Tl_(0.3))_2Ba_2(Y_x, Ca_(1-x))Cu_2O_(8-2#delta#) (x = 0.4,0.6,0.8 and 0.9), while two other series were prepared by annealing (Hg_(0.7), Tl_(0.3))_2Ba_2(Y_(0.8), Ca_(0.2))Cu_2O_(8-2#delta#) and (Hg_(0.6), Tl_(0.4))_2Ba_2Ca_2Cu_3O_(10-2#delta#) samples in Ar. The crystal structures of the samples were determined by x-ray Rietveld refinement. The variation tendencies of their lattice parameters as well as several particular inter-planar distances with the change of the hole doping level in these three series were investigated and compared with one another Based on the comparison, a qualitative explanation for the structural evolution tendency under hole doping for these series was proposed.