strongly connected grains and without AEC phases by a simple electrophoretic deposition technique. It is therefore thought that the present results may provide a significant breakthrough for the high-T c superconducting film and wire fabrication industries.
Experimental
Pristine Bi 2 Sr 2 CaCu 2 O 8+y (Bi2212) was prepared by a conventional solid-state reaction [10Β±14]. As a secondary precursor, HgI 2 intercalates were synthesized through hardΒ±soft acidΒ±base reactions, as documented in our previous reports [10Β±14]. To intercalate (PyC 12 H 25 ) 2 -HgI 4 (where Py = pyridine), the HgI 2 -intercalates were mixed with a three-times molar excess of Py-C 12 H 25 I, and then a few drops of analytical grade (Β³ 99.8 % purity) acetone were added to the mixture. Each of the resulting mixtures was reacted in a closed ampoule at 50Β±60 C for 48 h. Finally, the dark-brown gel-like products were washed with acetone to remove the excess organic salts on the crystal surfaces. Exfoliation of the bisalkylpyridinium tetraiodomercurate [(Py-C 12 H 25 ) 2 HgI 4 ] intercalates was carried out by sonicating them at 28 kHz in acetone solvent, which was kept in an ice bath to prevent overheating of the suspension. For the fabrication of superconducting films and microwires, the exfoliated Bi2212 nanosheets in acetone solvent were electrophoretically deposited onto Ag substrates with a power-source meter (Keithley 2400) using a Pt plate (2 cm 5 cm) as a counter-electrode. As-deposited films and wires were subsequently heated at 840 C for 12 h.