Smooth Transition of Nb₃Al Wire Fed by AC Current in High Magnetic Field

Abstract

The aim of the present work is of giving an overall view of the behaviour of the Nb₃Al multilayered wire fed by an ac current in the presence of a constant external magnetic field as far as the losses are concerned. As previously described¹ this wire is obtained by the so-called “jelly rolled method” and the A15 phase is promoted through a low-temperature thermal treatment; the final product is a filament consisting of irregular alternate sheets of Nb and Nb₃Al that are both superconducting below the critical temperature and critical field of Nb. One can expect some changes in the properties of the ware when these critical parameters are exceeded. A previous work ² was concerned with the effect of increasing temperature, this one deals with the influence on the critical current and on the losses of an external magnetic field B in the range O ⪕ B ⪕ 6T.