GB/T 39843-2021 Active

This standard specifies the method of measuring the local critical current density (Jc) and its distribution of large-area high-temperature superconducting (HTS) films using the three-harmonic voltage induction method. The most important factors in accurate measurement are determining the Jc value in the liquid nitrogen temperature zone by the electric field strength criterion and obtaining the current-voltage characteristics through the frequency dependence of Jc. Although Jc can be measured in the presence of a DC magnetic field [20,21], this standard only applies to cases without a DC magnetic field.
Essentially, this standard measures the critical surface current of the superconducting film, which is the product of Jc and the thickness d of the superconducting film. The measurement range and resolution of Jcd for high-temperature superconducting films are as follows:
——Jcd: from 200 A/m to 32 kA/m (based on experimental results, not limited to);
——Resolution: 100 A/m (based on experimental results, not limited to).