Synthesis of superconductors from soluble metal oxo alkoxide precursors

Abstract

Soluble metal oxo alkoxide precursors are useful for the production of homogeneous, micron-sized YBa₂Cu₃O_7−x powders and the fabrication of superconducting YBa₂Cu₃O_7−x films on large area and nonplanar substrates. This paper describes the synthesis and chemistry of a series of soluble metal oxo alkoxide precursors for the YBa₂Cu₃O_7−x superconducting material and the effect of the thermal processing conditions on the formation of the superconducting phase. We have found that the direct conversion of the metal oxo alkoxide precursors to an amorphous or crystalline YBa₂Cu₃O_6.5 phase without the intermediate formation of the individual metal oxides or carbonates allows the formation of the superconducting phase at temperatures as low as 720 °C. The prevention of the intermediate formation of the metal oxide and carbonate phases is achieved by the controlled thermolysis of the metal oxo alkoxide precursors in an inert atmosphere. The precursors have potential use in the low-temperature deposition of films on large area or nonplanar surfaces and for the production of homogeneous powders.