Preparation of superconductingYBa2Cu3O7from the corresponding metal formates

Superconductive ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ was prepared from a mixture of yttrium, barium, and copper (II) formates in flowing oxygen. The product was obtained by single-cycle heating to 920 °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 95 K 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.