Kim-Type Critical State Models and Critical Currents of Thallium Based Superconductors

W.M. Woch a, R. Zalecki a, A. Kołodziejczyk a, O. Heiml b, H. Sudra b and G. Gritzner b a Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, PL-30-059, Kraków, Poland b Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University, A-4040 Linz, Austria

Full Text PDF

Received: 6 11 2007;

The two extended formulae in the power form of the Kim critical state model were used to fit the critical currents versus the dc applied magnetic field. Two samples of thallium based superconductors: the (Tl0.6Pb0.24Bi0.16)(Sr0.9Ba0.1)2Ca2Cu3Oy film on single-crystalline lanthanum aluminate and the bulk (Tl0.5Pb0.5)Sr2(Ca0.8Gd0.2)Cu2Oy were chosen to test the models. The formulae were compared to the percolation model described by the exponential expression. The first model fits the experimental data better for the thallium based film whereas the second approach is better for the thallium based bulk sample.

DOI: 10.12693/APhysPolA.114.99 PACS numbers: 74.72.Jt, 74.25.Sv, 74.25.Ha