[Zurück]

J. Viljamaa, L. Rostila, P. Kovàc, T. Melisek, A. Hinterberger, M. Reissner:
"Comparison of Different Critical Current Density Models for Undoped Monofilamentary Ti-Sheathed MgB₂ Tapes";
Journal of Superconductivity and Novel Magnetism, 24 (2011), S. 287 - 297.

Two Jc dependency on B models with physical
backgrounds and two semiempirical models are fitted in
fieldsB >1.5 T to critical current measurements. The measurements
were previously performed on various undoped
titanium sheathed monocore MgB2 tapes. The models are
fitted to magnetic measurements performed at temperatures
ranging from 4.2 to 15 K and to transport measurements in
both parallel and perpendicular directions.
These parameters of the introduced models have clear
physical interpretations, such as, the zero field critical current
density, the zero resistivity field, and the steepness factor.
The parameters are solved through numerical optimization.
The goal is to find a model with simple parameters
that produce computed values which match those observed
through direct measurements. In the future, these parameters
can be used to gather information about pinning, to compare
the performance of the conductors, and to develop these further.
The results indicate that many kind of models are sufficient
to describe the Jc(B) behavior of different kinds of
tapes and measurement methods in various temperatures.
They also enable the reconstruction of the Jc(B) dependence
even from a limited number of data points or a narrow
measurement range.

http://dx.doi.org/10.1007/s10948-010-1021-4