Structure, doping and superconductivity in HgBa2CaCu2O6+δ (Tc ⩽ 128 K)

Oxygen ordering in the high-Tcsuperconductor HgBa2CaCu2OMendonça1, Correia2, Haas3 et al. 2011Phys. Rev. B

“…Additionally, these should be short range effects since the ordering cannot build up coherently too far without originating deformed superlattices which would be seen by diffraction techniques. In fact, in the numerous neutron diffraction and X-ray scattering studies 18,28,32,36,37 there was no indication nor suggestion for the existence of molecules at the Hg planes. In addition, the non uniform dopant local distribution, as found in this work, complicates the analysis via techniques that make use of coherence or average oxygen concentration.…”

Sol–gel synthesis, structural and superconducting properties of (Hg1−ySey)Sr2(Y1−xCax)Cu2O6+δ

“…After this discovery, the synthesis work expanded in several directions, leading to an exploration of the family of superconductors based on single-mercury oxygen layers, HgBa 2 Ca nÀ1 Cu n O 2n+2+d (n ¼ 1-7). The second member HgBa 2 CaCu 2 O 6+d (Hg/Ba-1212) has T c(onset) ¼ 127 K [6][7][8]. It was shown that a rare earth containing 1212 phases is also superconducting if a heterovalent of R 3+ replacement by Ca 2+ is made in sufficient amounts 440% [9,10].…”

Synthesis of Hg-Re-Ba-Ca-Cu-O superconductors by a two-step method

“…Manuscript received August 25, 1996 This work 'was supported in part by the National Science Foundation under Grant DMR-952623 1 In all techniques, critical parameters for the superconducting phase formation are precursor purity, annealing temperature, annealing time, Hg vapor pressure, and oxygen partial pressure [SI. The synthesis of the superconducting Hg1212 and Hg1223 phases requires extraordinary care during all steps of the sample preparation to minimize the exposure of the precursor materials to moisture and carbon dioxide [9]. Since the degree of sensitivity is not fully understood, the reproducibility of experimental results is often low.…”