The urea combustion method in the preparation of precursors for high-TC single phase HgBa2Ca2Cu3O8+δ superconductors

An alternative sol–gel route for synthesizing precursors of mercury based superconductors is presented. This route is based on urea as a combustion agent and has been applied in the synthesis of HgBa2Ca2Cu3O8+δ (Hg-1223). Moreover, the effects of the precursor preparation on the synthesis of Hg-1223 were studied. This method is further compared with other sol–gel routes used in the synthesis of this family of compounds.

► Urea appears as an alternative sol–gel agent to produce Ba–Ca–Cu–O precursor powders.
► The urea route allowed complete decarbonation in shorter times.
► This route does not need the use of special annealing atmospheres.
► Another advantage of this route is the much lower cost of the reactants.