Alternating field losses in Nb3Sn multifilamentary superconductor

Transverse alternating field losses at 4.2K have been measured from 0.5 Hz to 10 kHz in a Nb3Sn multifilamentary superconductor in bias fields to 5 Tesla. The 0.020 inch diameter sample was prepared by heat treating a Cu, Nb-1 wt % Zr, CuSn composite at 700°C for 20 hours to form Nb3Sn on the inside surface of the annular filaments. Metallurgical studies have been made to determine the Sn distribution and to estimate the thickness of the Nb3Sn layer. The Ic-H curve and resistive and inductive transition curves are presented. The losses are analyzed with respect to the present loss theories using the conductor characteristics measured and excellent agreement between experiment and theory is achieved.