Temperature dependence of vortex flux pinning with γ-irradiation in polycrystalline Tl-2223

Abstract

Hysteresis loop measurements of superconducting polycrystalline samples of Tl-2223 were carried out at various temperatures. Using the magnetization remanence (M R ) as measurement of the maximum vortex flux pinning at each temperature, our results reveal that the vortex flux pinning forces show two distinct behaviours of M R with temperature, a linear behaviour with t at high temperatures and an exponential behaviour with t β at low temperatures, where t = (1 − T /T c ) and β is constant of order 8. The effect of γ -irradiation shows six-fold enhancement in the vortex pinning over all temperatures up to T c . This increase in the pinning forces is attributed to the induced defects introduced by the γ -irradiation. The same enhancement in the pinning forces at all temperatures implies constant defects induced by γ -irradiation.

Effects of gamma irradiation on the superconducting properties of TlBa 2 Ca 2 Cu 3 O x tapes

“…The ratio α/β depends on the microstructure of the sample. The temperature dependence of the vortex flux pinning with γ-irradiation on polycrystalline Tl-2223 samples was studied [11]. γ-irradiated sample showed enhancement in the pinning at the same temperature by introducing defects that reduce the effect of weak links between grains which act as a new pinning agents to prevent motion of vortices.…”