Nonlinear magnetic diffusion in single-domain YBCO cylinders under pulsed field conditions

Author

Askew, Thomas R. ; O´Daniel, Jennifer C. ; Weber, Jonathan M. ; Cha, Y.S.

Author_Institution

Phys. Dept., Kalamazoo Coll., MI, USA

Volume

15

Issue

2

fYear

2005

fDate

6/1/2005 12:00:00 AM

Firstpage

3758

Lastpage

3761

Abstract

A step-function increase in magnetic field has been applied to various single-domain Y-Ba-Cu-O rings and disks at 77 K. The magnetic field in the center of these structures exhibits an exponential approach to an equilibrium value, as predicted by simple diffusion theory. The measured time constants are in the millisecond range and show nonlinear behavior, as predicted in recently advanced theories of magnetic diffusion under flux flow conditions. Measurements of trapped magnetic field, critical current density, and current-voltage (I-V) characteristics are compared to results obtained by measurement of magnetic diffusion. The single-domain structures are intended for use in penetration-type fault current limiters, an application where the magnetic diffusion time constants have a strong influence on device design.

Keywords

barium compounds; critical current density (superconductivity); diffusion; high-temperature superconductors; magnetic flux; penetration depth (superconductivity); yttrium compounds; 77 K; Y-Ba-Cu-O; critical current density; current-voltage characteristics; exponential approach; flux flow condition; magnetic flux penetration; magnetic shielding; nonlinear magnetic diffusion; penetration-type fault current limiters; pulsed field conditions; single-domain YBCO cylinders; single-domain structures; step function; trapped magnetic field; Critical current density; Current measurement; Density measurement; Fault current limiters; Fluid flow measurement; Magnetic field measurement; Magnetic flux; Nonlinear magnetics; Time measurement; Yttrium barium copper oxide; Magnetic diffusion; magnetic flux penetration; magnetic shielding; single-domain YBCO cylinders;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2005.849424

Filename

1440489