ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Magnetization measurements of the critical current density Jc in Nb 47 wt % Ti with Nb artificial pinning centers revealed that the shape and magnitude of the field dependent magnetization hysteresis ΔM(H) was a strong function of the sample length and that ΔM(H) for short wire samples was up to six times smaller than for long wires. This is caused by the strong anisotropy of the critical current density Jc. The magnitude of Jc flowing perpendicular to the wire axis J⊥ was deduced to be 50–175 times smaller than the longitudinal current density J(parallel). The source of the anisotropy lies in the anisotropic flux pinning microstructure of the wires. When the magnetization current crosses perpendicular to the filament axis at each end of the wire, the Lorentz force is parallel to the pinning center axis. The pinning force is weak in this direction and J⊥ is correspondingly small. The technologically important critical current density is the longitudinal current density J(parallel). It can be extracted from magnetization measurements only in the case of large length to diameter filaments, as is quantitatively analyzed here. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.362963
