Levitation effects involving high T c thallium based superconductors

Abstract
The thallium based superconductor Tl2Ca2Ba2Cu3O10+y has been shown to exhibit very stable and unusual levitation equilibria in various arrangements involving this material and permanent magnets. Attractive and repulsive forces are evident in experiments in which samples are levitated above and below magnets. Photographs of these experiments and approximate quantitative discussions of the results are given.