MAGNETIC-RELAXATION AND INTRINSIC PINNING IN A SINGLE-CRYSTAL OF BI2SR2CACU2OX

Magnetic-relaxation experiments were performed on Bi2Sr2CaCu2Ox Single crystals with the direction of the field parallel to the ab plane. Based on the relaxation data, we have obtained relationships between the activation energy U and the current density j by an approach we developed previously. We found that the activation energy has a logarithmic dependence on j in a wide regime of driving force. It has been reported that CuO2 planes in high-T(c) superconductors can act as strong intrinsic pinning centers and that the relation U approximately U0ln(j(c)/j) may describe such a pinning mechanism. Our experimental results have shown good agreement with such a physical model of intrinsic flux pinning.4795414541