I-V characteristics and the electric-field effect in melt-grown YBa2Cu3Ox/Y2BaCuO5 HTSC crystals

The effect of an electric field E = 120 MV/m in the electrode-insulator-sup erconductor system on I-V curves obtained at 77 K on two types of single-cr ystal samples cut from monolithic superconducting YBa2Cu3Ox/Y2BaCuO5 has be en studied. The Y211 nonsuperconducting phase in the ingot was in the form of precipitates approximate to 1 mu m in size. It has been found that an el ectric field applied to samples with a comparatively low Y211 content (volu me fraction 8%) does not affect the critical current I-c while reducing the resistance R at currents slightly above I-c. In samples containing more th an 35% Y211 phase, electric field results in an increase of I-c and a decre ase of R for I > I-c. Data on the critical temperature T-c and the temperat ure dependence of I-c have also been obtained. (C) 2000 MAIK "Nauka/Interpe riodica".