Measurement of AC Penetration Depth in Superconducting Wires with Fine Filaments
The critical state model of the Bean-London type predicts that the AC hysteresis loss energy density in the superconducting filaments of the diameter d f is given by W = 4μoH/3J c d f for the AC field amplitude H m smaller than the penetration field, H p = J c d f/2. However, this prediction does not agree with experimental results for multifilamentary wires with fine superconducting filaments for AC use. That is, the AC loss energy density is much smaller than the above prediction and the region of H m in which W is proportional to H m 3 extends up to much larger value than H p. This deviation was found to be caused by the reversible fluxoid motion inside the pinning potential well.1
KeywordsCritical Current Density Magnetization Hysteresis Magnetic Field Dependence Critical State Model Filament Diameter
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