Critical current density of MTG-YBa2Cu2.99Li0.01Oy crystals

The temperature dependence of AC susceptibility has been measured as a function of AC amplitude and frequency at zero DC field in MTG-YBa2Cu2.99Li0.01Oy crystals. We try to extract the critical current density near Tc from the real component of AC susceptibility curves. The temperature dependence of critical current density followed Jc(T) = 1.548 × 1010 (1 − T/87.3)1.38 (A/m2), which is good agreement with Jc′(T)=1.492×1010(1-Tp/87.3)1.36(A/m2) obtained from the traditional “loss-maximum” approach. The effective activation energy near Tc is also discussed.