ABSTRACT
In this chapter, the authors describe one of the most important characteristic behaviors of any superconductor: magnetism. They note that good-quality Thallium single crystals exhibit ideal diamagnetic behavior. The authors also discuss how magnetism provides microscopic information about the superconducting ground state. They discuss the progress that has been made in understanding the magnetic properties of Thallium materials; however, much work remains. To understand the consequences of zero resistance and of zero inductance, the magnetic behavior are considered under identical conditions. In most respects the magnetic properties of thallium-based superconductors are similar to those of other copper oxides. Diamagnetism is a strongly temperature-dependent property associated directly with the superconducting transition. The authors described flux exclusion or diamagnetic shielding and have shown that in a good-quality thallium superconductor, diamagnetism is ideal.
