A new experimental technique to evaluate perpendicular-field losses of superconducting tape wires with meter-class length

This paper describes a new method for experimental evaluation of AC losses of superconducting tape-shaped wires in a perpendicular magnetic field. This technique is similar to a usual pickup-coil method for transverse-field loss measurements of superconducting round wires although the perpendicular magnetic field is applied to the sample wire wound as a pancake coil. First, the interlinkage magnetic flux into a pair of pickup coils due to the uniformly magnetized sample is analytically estimated. On the basis of the preliminary discussion, a new apparatus is designed and fabricated for the perpendicular-field loss measurements of superconducting tapes. The perpendicular-field losses of a Bi-2223 Ag-sheathed tape are also measured at liquid nitrogen temperature, and the obtained results are compared with those by a conventional experimental system.