CRITICAL-CURRENT IN ELECTROPHORETICALLY DEPOSITED THICK-FILMS OF YBCO SUPERCONDUCTOR

Thick films of YB2Cu3O7-delta (YBCO) superconductor have been prepared by the electrophoretic deposition technique using a flexible silver strip as the substrate. Effects of several deposition parameters, e.g., time of deposition, particle size of the powder, number of layers deposited, etc., on the various properties of the films have been studied in detail. Microstructural investigation of the films indicates extensive grain growth and recrystallization phenomena particularly in films of large thickness. The microstructural morphology changes significantly as the thickness decreases. The transport J(c) (at 77 K, B = 0) increases from almost-equal-to 450 A/cm2 for a film thickness of almost-equal-to 65 mum to > 4000 A/cm2 for a reduced thickness of almost-equal-to 3 mum. Possible reasons for this dimensional dependence are discussed.