Synthesis of mercury cuprates

Abstract

Mercury cuprates have very interesting potential applications that have not been thoroughly explored until now because of the complexity of their synthesis. This paper presents an overview of recent results concerning their processing. At first, a simple sol-gel technique is described that permits one to easily and intimately mix the precursors. The method uses the gelification of an inorganic solution of the cations by acrylamide polymerization. Mercuration of the precursor at moderate pressures (<2-5 MPa) is then discussed. The control of the total pressure during the synthesis by a simple method is shown, and this enables one to quantify some important parameters of the synthesis and to optimize the superconducting properties. This method has been also used successfully to incorporate mercury into layers of precursors and then to form thick layers of superconducting (Hg, Re)-1223, c-axis oriented. Finally, mercuration at higher pressures (up to 6 GPa) is considered and the case of the double mercury layer Hg-2212 is discussed in connection with the oxygen content of the reactants.

Crystal Growth and Characterization of the Model High‐Temperature Superconductor HgBa2CuO4+δ

“…In order to improve the homogeneity of the precursor, a third approach, the sol-gel method, was employed by several groups. [17,18,24] However, the use of an organic acid or polymer can easily contaminate the precursor with carbon. A fourth method uses a mixture of Ba(NO 3 ) 2 and CuO.…”

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

“…A stoichiometric mixture of HgO and Ba 2 CaCu 2 O 6+δ was placed in a gold capsule and then treated at 1.6 GPa, 1073 K for 1 hour, using a Conac type hydraulic press 23 . To control samples quality, X-ray diffraction (XRD) measurements have been performed using a Siemens D5000 diffractometer, in transmission mode, with Cu K α radiation (λ=1.541 Å), in a 2θ range between 10…”

Perturbed Angular Correlations Studies in the HgBa2CaCu2O6+δ high-TC Superconductor

“…Hg-1212 polycrystalline samples were synthesized using the high pressure -high temperature technique (HP-HT) [13] at 1.6 GPa, 1073 K for one hour. The quality of the samples was controlled via X-ray diffraction (XRD) measurements, which were performed using a Siemens D5000 diffractometer, with Cu K α radiation (λ =1.541Å), in a 2θ range between 10 • and 90 • .…”