Fabrication of oxocuprate superconductor microelectrodes for sub-Tc use

The technique of partial resin encapsulation is described for the direct fabrication of cryorobust oxocuprate microelectrodes from bulk ceramic samples, here Bi2Sr2CaCu2O8-δ, Bi2Sr2Ca2Cu3O10-δ. Cyclic voltammetry is used in tests of the electrochemical response at 295 K (ferrocene in acetonitrile/NBu4BF4), affording approximated disk radii 2.9, 37.0, and 32.5 microm, and at 123 and at 103 K (ferrocene in chloroethane/tetrahydrofuran/LiBF4). Some nonideality in the 295 K responses results from electrode porosity and, at the smallest electrodes, defects in the HTSC/resin seal. Acceptable sub-Tc responses show these problems to be irrelevant in the high viscosity of the electrolytes at low temperature. These microelectrodes usefully advance the emerging study of electrochemistry on superconducting electrodes by responding to free-solute electroactives at <Tc