Study of Resistive Superconducting Transition of Thallium Based Superconductors
Sprache des Titels:
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: ?T = CHm + ?T0. 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 Tc as well as for temperatures close to the zero resistance critical temperature.
PACS numbers: 74.72-h, 74.40n, 74.20.De, 74.25.Ha