Influence of pelletization pressure on the structural and transport properties of TICaBaCuO superconductors

An investigation is reported of the effects of pelletization pressure on the structural and transport properties of polycrystalline TlCaBaCuO samples with nominal composition of Tl2Ba2Ca2Cu3O10-x. The measurements reveal the following interesting results as the pelletization pressure increases: (1) the volume fraction of self-formed Tl-2212 phase decreases and the amount of target Tl-2223 phase increases; and (2) the links between grains become stronger. Consequently, energy dissipation on grain boundaries decreases and critical current increases. The paper also discusses the applicability of thallium samples as magnetic field sensors. It was found that the samples pelletized at low pressures become more sensitive to a magnetic field compared to those pelletized at high pressures. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.