Submicrometer Superconducting YBa2Cu3O6+x Particles Made by a Low-Temperature Synthetic Route.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Superconductivity

Background:

• Superconducting orthorhombic YBa(2)Cu(3)O(6+x) (orthorhombic 123) is typically formed by oxidizing the oxygen-deficient tetragonal phase (tetragonal 123).
• A reliable synthesis route for high-quality tetragonal 123 is crucial for producing superconducting orthorhombic 123.

Purpose of the Study:

• To establish a novel synthetic pathway for producing superconducting orthorhombic YBa(2)Cu(3)O(6+x).
• To demonstrate the feasibility of using solution-derived, carbon-free precursors for this synthesis.

Main Methods:

• Decomposition of solution-derived, carbon-free precursors (hydrated oxides, hyponitrites) at 650–700°C in an inert atmosphere to yield tetragonal 123.
• Subsequent oxidation of the synthesized tetragonal 123 phase at 400°C to produce orthorhombic 123.
• Characterization of superconductivity using Meissner effect and specific-heat measurements.

Main Results:

• A reproducible synthetic route was developed to produce tetragonal YBa(2)Cu(3)O(6+x) from carbon-free precursors.
• Oxidation of the tetragonal phase yielded submicrometer particles of orthorhombic YBa(2)Cu(3)O(6+x).
• The resulting orthorhombic 123 material exhibited superconductivity with a T(c) onset of approximately 87 K.

Conclusions:

• The developed method provides an effective route to synthesize superconducting orthorhombic YBa(2)Cu(3)O(6+x) via an intermediate tetragonal phase.
• The use of solution-derived precursors offers a controlled and potentially scalable approach for producing high-quality superconducting materials.
• This work confirms the established relationship between the tetragonal and orthorhombic phases in YBa(2)Cu(3)O(6+x) and its superconducting properties.