Non-power-law I-V characteristics in Ca-doped polycrystalline Y1-xCaxBa2Cu3O7-delta

作者：Xu KX^*; Qiu JH; Shi LY

来源：Superconductor Science and Technology, 2006, 19(2): 178-183.

DOI：10.1088/0953-2048/19/2/005

Experiments reveal that there is a non-ohmic dissipation behaviour in the Ca-doped polycrystalline Y1-xCaxBa2Cu3O7-delta even at temperature T = 20 K. This non-ohmic dissipation seems to come from the vortex excitation along the grain boundaries and appears in anomalous I-V characteristics with a non-power-law behaviour at temperatures below 60 K, and then with a power-law behaviour as the temperature approaches T-c. This abnormal behaviour cannot be explained by the thermal flux creep model. We suppose that a giant flux motion along the grain boundaries might be responsible for this anomalous non-ohmic dissipation behaviour. A modified I-V relation was worked out based on Larkin's collective pinning model, and the analytical I-V curves were found to be coincident with the experimental curves quite well. This confirmed that the vortex excitation process along the grain boundaries in Ca-doped polycrystalline Y1-xCaxBa2Cu3O7-delta might be described with a modified collective pinning model.

• 出版日期2006-2
• 单位上海大学