TY - RPRT TI - Critical currents in polycrystalline Y Ba{sub 2}Cu{sub 3}O{sub 7-x}: Self-field and grain size dependence AB - The variation of critical currents (I{sub c}) and their distributions (CCD) with thickness (t) has been investigated for two high quality YBa{sub 2}Cu{sub 3}O{sub 7-x} samples with different average grain size (AG{approx_equal}10 and 30 {mu}m for samples S{sub 1} and S{sub 2} respectively) in the temperature range 78-90K and in the applied magnetic field H<50 0e. The critical current density (J{sub c}) for S{sub 1} initially increased but later on leveled off on reducing the thickness, whereas for S{sub 2} remained essentially unchanged even after three-fold reduction in thickness. Since the other parameters related to macroscopic homogeneity have not changed on reducing the thickness of the samples, the variations of J{sub c} are interpreted in terms of thickness and grain size dependent self-field effects. The same model explains well the changes of CCD curves with thickness and may also explain the variation of J{sub c} with the grain size, as reported recently for ceramic YBaCuO samples. (author). 18 refs, 7 figs, 2 tabs. AU - "Babic, E" AU - "Prester, M" AU - "Dobrac, D" AU - "Marohnic, Z [Zagreb Univ., Zagreb (Yugoslavia). Inst. of Physics]" AU - "Bernik, S [Institut Jozef Stefan, Ljubljana (Yugoslavia)]" AU - "Nazar, P" AU - "Stastny, P" AU - "Matacotta, F C" KW - "75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY" KW - "36 MATERIALS SCIENCE" KW - "HIGH-TC SUPERCONDUCTORS" KW - "CRITICAL CURRENT" KW - "BARIUM OXIDES" KW - "CERAMICS" KW - "COPPER OXIDES" KW - "EXPERIMENTAL DATA" KW - "GRAIN SIZE" KW - "MAGNETIC FIELDS" KW - "TEMPERATURE DEPENDENCE" KW - "YTTRIUM OXIDES" KW - "665411" KW - "360207" KW - "BASIC SUPERCONDUCTIVITY STUDIES" DO - https://doi.org/ UR - PB - CY - IAEA PY - 1991 DA - 1991-10-01 LA - English J2 - [] VL - C1 - International Centre for Theoretical Physics (ICTP), Trieste (Italy) C2 - C3 - IC-91/345 C4 - C5 - OSTI; NTIS (US Sales Only); INIS L3 - Other Information: PBD: Oct 1991 ER -