XANES study of the dependence of the hole density on the superconducting properties of Hg (1212) and the Hg oxycarbonate systems

5^th World Congress on Smart and Emerging Materials

April 19-20, 2018 Dubai, UAE

Sumit Kumar Gupta

University of Rajasthan, India

Accepted Abstracts: J Material Sci Eng

Abstract :

The mercury based superconducting cuprates which represents a fabulous source for the research of new high Tc superconductors have been extensively studied for the past some years just after the discovery of the superconductivity in the mercury cuprate HgBa2CuO4+�´. It was realized that the synthesis of the mercury based superconductor is difficult because of its highly metastable character. As a result, the high pressure synthesis was considered to be favorable for the synthesis of these materials. In fact, such metastability may be connected not only with the volatility of the mercury oxide, but also with the dumbbell coordination of Hg(II), that implies a large oxygen deficiency at the level of the mercury layers. The introduction of foreign cations on the mercury sites with higher oxidation state should allow additional oxygen to intercalated and consequently should increase the stability of such structures. The investigation of mixed Hg-M cuprates and copper oxycarbonates, where M is a transition element is based on these considerations. However, despite the above difficulties in their preparation, the Hg-based compounds have received much attention because of their high transition temperature at normal pressure and substantially increase in it with pressure. Substitution of transition elements for the Hg has allowed numerous superconductors for which the Tc depends upon their oxygen stoichiometry and the chemical bonding. Thus the knowledge of their electronic structure is absolutely important for understanding their properties. sumitguptagit@gmail.com