IEC 61788-17-2021 Superconductivity – Part 17: Electronic characteristic measurements – Local critical current density and its distribution in large-area superconducting films

IEC 61788-17-2021 Superconductivity – Part 17: Electronic characteristic measurements – Local critical current density and its distribution in large-area superconducting films. This part of IEC 61 788 specifies the measurements of the local critical current density (J c ) and its distribution in large-area high-temperature superconducting (HTS) films by an inductive method using third-harmonic voltages. The most important consideration for precise measurements is to determine J c at liquid nitrogen temperatures by an electric-field criterion and obtain current-voltage characteristics from its frequency dependence. Although it is possible to measure J c in applied DC magnetic fields [20] [21 ], the scope of this document is limited to the measurement without DC magnetic fields. This technique intrinsically measures the critical sheet current that is the product of J c and the film thickness d. The range and measurement resolution for J c d of HTS films are as follows. – J c d: from 200 A/m to 32 kA/m (based on results, not limitation). – Measurement resolution: 1 00 A/m (based on results, not limitation). 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60050-81 5, International Electrotechnical Vocabulary – Part 815: Superconductivity (available at <http://www.electropedia.org>) 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60050-81 5 apply, some of which are repeated here for convenience. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 critical current I c maximum direct current that can be regarded as flowing without resistance practically Note 1 to entry: I c is a function of magnetic field strength, temperature and strain. [SOURCE: IEC 60050-81 5:201 5, 81 5-1 2-01 ] 3.2 critical current criterion I c criterion criterion to determine the critical current, I c , based on the electric field strength, E, or the resistivity, ρ Note 1 to entry: E = 1 0 µV/m or E = 1 00 µV/m is often used as electric field criterion, and ρ = 1 0 -1 4 Ω · m or ρ = 1 0 -1...