Eddy Currents in Pulsed Field Measurements
R. Grössinger, M. Küpferling, P. Kasperkovitz, A. Wimmer, M.Taraba,
W.Scholz, J.Dudding, P. Lethuillier, J.C.Toussaint, B. Enzberg-Mahlke,
W.Fernengel, G. Reyne
J.M.M.M. (2001) submitted to JEMS'01 Conf. Grenoble Aug. 2001, paper E116.
In pulsed field magnetometry the error due to the magnetization of
eddy currents is a serious problem. Therefore systematic experimental
and theoretical studies of the magnetization due to eddy currents
in metallic samples were performed. Eddy current measurements were
performed in cylindrical and spherical samples of Cu and Al.
The eddy currents were determined by magnetization measurements using
two different pulse durations (9.1 ms and 15.7ms) and applying a
bipolar field with an amplitude of 5.2 T. The samples were measured
in the as cast state (after machining) as well as after a heat
treatment (400t = 2h). The eddy currents were analyzed in three
i) Analytical calculation of the eddy currents in metallic spherical
samples agrees with the experiment within 10%.
ii) The "eddy current" magnetization as a function of dH/dt
exhibits a linear dependence. Analytic calculations proofs
that the slope is proportional to the specific resistivity of the material.
iii) The eddy currents were also analyzed using a 2D-software
package called FEMM. The shape of the magnetization due to the
eddy currents showed theoretically and experimentally the same shape.
<< Back to list of publications
<< Back home
webmaster: fidler (at) tuwien.ac.at
Oct. 5, 2001