ACTA

Study of Resistive Superconducting Transition of Thallium Based Superconductors

W.M. Woch^a, R. Zalecki^a, M. Chrobak^a, A. Kołodziejczyk^a and G. Gritzner^b
^aSolid State Physics Dept., AGH University of Science and Technology, al. Mickiewicza 30, PL 30-059, Kraków, Poland
^bInstitute for Chemical Technology of Inorganic Materials, Johannes Kepler University, A 4040 Linz, Austria

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A width and shape of resistive transition as well as thermal fluctuations of the thallium based superconductors were analyzed theoretically. The applied magnetic field widens the resistive transition according to the following formula: ΔT = CH^m + ΔT₀. The exponent m fluctuates around 2/3 and depends on vortex structure and strength of the pinning force. The shape of the resistive transition was fitted by two models: the first one based on Ambegaokar-Halperin theory and the other one based on Anderson-Kim theory expressed by the exponential formula. Critical fluctuations were analyzed on the basis of magnetoresistance measurements results. The critical exponents have been calculated above the critical temperature T_c as well as for temperatures close to the zero resistance critical temperature.

DOI: 10.12693/APhysPolA.121.789
PACS numbers: 74.72-h, 74.40n, 74.20.De, 74.25.Ha