Experimentally Determined Magnetization ac Losses of Mono and Multifilamentary MgB2 Wires

Magnetization AC loss measurements have been performed by the calibration free method on mono, 19 filaments un-twisted and 19 filaments twisted MgB2 superconducting wires with magnetic fields perpendicular to the wire axis at various frequencies and temperatures between 24 and 40 K. AC losses were also calculated based on critical state model for mono-filamentary Nb sheathed MgB2 wire with conditions corresponding to experiments. Good agreement is observed between model and experimental data. AC losses go through a peak when the wire was cooled below T-c. In terms of AC magnetization losses, the twisted wire has the minimum losses in order of 10(-5) J/m at 30 K in AC magnetic field with 20 mT amplitude.