Measurements have been made of the low-field ac and dc superconducting properties of thin films of electron-beam-evaporated Nb3Sn. Comparison of the 50-Hz hysteretic loss and flux entry waveforms with the measured field-dependent critical current indicates that a modification of the usual critical state model with a uniform surface barrier is necessary. A model based upon a nonuniform flux distribution, consistent with the observed morphology, is presented. Its success in describing the low-field properties of this sytem and its importance to related materials in which the superconducting properties are strongly dependent upon the microstructure are discussed.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)