Preparation of Superconducting YBa sub 2 Cu sub 3 O sub 7 From the Corresponding Metal Formates

Superconductive YBa sub 2 Cu sub 3 O sub 7 was prepared from a mixture of yttrium, barium, and Cu(II) formates in flowing oxygen. The product was obtained by single-cycle heating to 920 deg C. Unlike conventional preparations, the orthorhombic phase is obtained without the requirement of an extended annealing period. Magnetic susceptibility measurements show the onset of superconductivity occurs at 95K with a magnetic-flux expulsion of 5% at lower temperatures. X-ray powder diffraction data show the material to be predominantly the orthorhombic phase, with excess BaO impurity and none of the tetragonal phase present. 6 ref.--AA