Hall sensor magnetometer measurements of Bi-HTS tapes for low AC loss applications

In order to reduce ac losses in Bi-2223 tapes twisted filaments and different kinds of oxide barriers around filaments have been developed. In this paper, the homogeneity and electromagnetic behavior of these tapes are studied. The magnetic flux density maps over current carrying samples are measured with Hall sensor magnetometer. The homogeneity of tapes is most easily visible when dc transport currents at different amplitudes and remanence currents after switching off the dc transport current are examined. Ac transport currents at 50 Hz are used to determine the current of full penetration. The results of different samples are compared and discussed in relation to the design-parameters of the tapes.