Published online by Cambridge University Press: 28 February 2011
A systematic study of the influence of oxygen depletion on the carrier concentration and the occurence of superconductivity in a single-phase 1–2–3 Y-Ba-Cu-Oxide material is presented. This is accomplished by successive measurements of the Hall and electrical resistivities, ac-susceptibility, and x-ray diffraction on the same sample, in which the oxygen deficiency is controlled and determined from thermogravimetry. With increasing oxygen depletion, we monitor how the 93K orthorhombic superconductor, with an estimated carrier concentration of 0.6·1022 carriers/cm3 at 100K, is transformed into a tetragonal semiconductor with a very low carrier concentration.