HgO as an internal oxygen source in Y1Ba2Cu3O7-δ

Abstract

This paper reports an alternative technique for preparing Y1Ba2Cu3O7-δ with uniform oxygen stoichiometry which eliminates the need for flowing oxygen during sintering. Our studies show that when HgO is added to the YBaCuO system it provides an abundant source of oxygen during sintering. Mercury diffuses out of the system leaving the crystal structure intact. We have thus been able to obtain a Tc (zero resistivity) of 90 K consistently in HgO doped YBaCuO specimens and sintered in air. An optimum value of HgO leads to a strongly coupled grain material. Resistivity, X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and a.c. susceptibility data are reported.