THE MAGNETIC FLUX DYNAMICS AT MAGNETOTERMAL INSTABILITY IN A
DISC SHAPE NbTi SUPERCONDUCTOR.
S. Vasiliev1, V. Chabanenko2, S. Piechota1, A. Nabiałek1, V. Rusakov3, H. Szymczak1.
1
Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warszawa,
Poland.
2
Physico-Technical Institute NAS, 72 R. Luxemburg str., 83-114 Donetsk, Ukraine.
3
Donetsk National University, 24 Universitetskaja str., 83-055 Donetsk, Ukraine.
Abstract
The magnetic flux dynamics of the NbTi-50% sample (diameter-14mm, height-4mm) have
been studied using pick-up coils wound directly on sample. The voltage from pick-up coils
(Ecoild/dt) was registered by the transient recorder. We have investigated the influence of
the eddy-current braking on the flux dynamics due to the thermomagnetic avalanche. These
experiments have been done using two cooper disks put on both sides of the superconducting
disc. Time duration and value of magnetic flux of jumps have been investigated at different
temperatures and wide range of the magnetic fields (up to 12T). It has been established that
the presence of the cooper discs decreases the value of the flux penetrated into sample Fig.1.,
and simultaneously increases the duration of the flux jump Fig.2.
Dependence of flux penetrated into sample
vs external magnetic field at T=4.2 K
Dependence of duration of jumps vs
external magnetic field at T=4.2 K