A theoretical study for temperature dependence of levitation force of high-T-c superconductors

The temperature effect on the levitation force of a cylindrical type-II superconductor was investigated theoretically by solving the critical state equation. Analytical expressions are obtained for the levitation force versus increasing temperature for zero-field-cooled (ZFC). Examining the behavior of levitation force-temperature curves the critical parameters are the critical current density, lower critical field and the pinning strength. The calculation qualitatively agrees with the experimental results for high-Tc superconductors. Employing exponential decay of the critical current density we have reproduced temperature- levitation measurements published in the literature. Some important macroscopic parameters may be obtained by fitting the expressions introduced in this paper with the experimental data. (C) 2012 Elsevier B.V. All rights reserved.