$J_{C}(B)$ Determination Method With the Help of the Virgin Magnetization Curve of a Superconducting Cylinder

It is well known that the critical current density
JC
of a superconducting material depends on the magnetic flux density
B
. For practical applications, it is essential to have accurate information about
JC
(
B
) , which can be obtained from different experimental techniques (transport current, hysteretic cycle, and ac susceptibility). This paper presents a simple and quick
JC
(
B
) experimental determination method for a superconducting cylinder. A first
JC
(
B
) experimental evaluation method consists of measuring the magnetization cycle
M
(
B
) and determining the width of this cycle for each value of
B
. This is generally done using the Bean model, where
JC
is considered constant. A more accurate method is presented in this paper. The cylinder first magnetization curve
M

₁
(
B
) is calculated with the Kim model [
JC
(
B
) =
JC
0/(1 + (|
B
|/
BC
0))] and with a linear model and compared with the measured first magnetization curve
M

_1mea
(
B
). In so doing,
JC
0 and
BC
0 are determined, and the results obtained using both
JC
(
B
) determination methods are compared and discussed.