Alternating field losses in mixed matrix multifilament superconductors

Author

Walker, M.S. ; Murphy, J.H. ; Carr, W.J., Jr.

Author_Institution

Westinghouse Research Labs, Pgh., PA

Volume

11

Issue

2

fYear

1975

fDate

3/1/1975 12:00:00 AM

Firstpage

309

Lastpage

312

Abstract

Losses were calculated for and measured at 4.2°K in two mixed-matrix superconductors for the cases of transverse applied alternating fields superimposed upon zero or 5T transverse bias fields. The 0.080 in. × 0.160 in. conductors are composites of copper-sheathed Nb-Ti filaments twisted every 5 cm within a copper-nickel matrix, where the copper-nickel to copper to superconductor ratio is nominally 4:4:1. The conductors differ only in the copper-nickel alloy of the matrix and the associated matrix conductivities, sigmamcalorimetric measurements were performed with alternating fields ranging in frequency, f, from 0.3 to 12,800 Hz and from 2500 to 4 oersteds in amplitude Hm. Eddy current losses consistent with the theory and proportional to $H_{m}^{2}f^{2}\\sigma _{m}$ and $H_{m}^{2}f\\deg /\\sigma _{m}$ were observed. The measured losses were found to be less than the calculated losses and within 45% of the calculated losses in all cases.

Keywords

Eddy currents; Hysteresis; Superconducting materials; Anisotropic magnetoresistance; Conductivity; Conductors; Eddy currents; Loss measurement; Magnetic field measurement; Magnetic fields; Magnetic hysteresis; Multifilamentary superconductors; Permeability;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.1975.1058568

Filename

1058568