Bi(2223) Ag sheathed tape Ic and exponent n characterisation and modelling under DC applied magnetic field
We use a dual channel digital lock-in to perform electrical measurement of AC losses at power frequencies. A DC magnetic field between 2 and 400 mT is applied with a varying angle from parallel to perpendicular to the tape surface, thus having a complete view of the loss behavior under DC applied field. Furthermore, the same experimental layout is used to acquire time series of current and voltage across the sample. Using a triangular input current, we measure and average the voltage, which then is fitted to a power law (I/Ic)^n. The measurements are repeated for the mentioned magnetic field and angle domain to give the dependencies of Ic and n with magnetic field and angle. For device modeling purposes, we can then express a phenomenological law giving Ic and n as a function of the applied magnetic field's intensity and direction.