Nonlinear alternating current susceptibility studies of high-T-c rings: Influence of the structuring method and determination of the flux creep exponent
S. Streubel et al., Nonlinear alternating current susceptibility studies of high-T-c rings: Influence of the structuring method and determination of the flux creep exponent, J APPL PHYS, 87(12), 2000, pp. 8621-8627
We have studied the influence of the patterning procedure on the critical c
urrent density of high-T-c YBa2Cu3O7-delta thin rings using the nonlinear a
c susceptibility method. At no applied dc magnetic field have we found that
laser ablation strongly degrades the critical current density whereas ion
beam etching has only a weak influence on it. From the measurements at diff
erent frequencies and at dc magnetic fields we analyzed the influence of fl
ux creep and obtained the field dependence of the flux creep exponent. Our
data reconfirm the recently observed scaling relation for the nonlinear sus
ceptibility response of type-II superconductors. (C) 2000 American Institut
e of Physics. [S0021- 8979(00)02312-4].