Yttrium barium copper oxide

Yttrium barium copper oxide is a family of copper-oxide ceramics whose superconducting properties depend strongly on oxygen content. Its best-known composition, YBa₂Cu₃O₇−δ, superconducts below about 93 K.

Cuprate superconductivity: Superconductivity in layered copper-oxide materials, including several families with transition temperatures above those of conventional superconductors. Yttrium barium copper oxide is a prominent cuprate whose superconducting behavior exposes shared features and material-specific differences.
High-temperature superconductivity: Superconductivity occurring at temperatures substantially above those of conventional metallic superconductors. Yttrium barium copper oxide helped establish that ceramic compounds could superconduct above liquid-nitrogen temperature.
Superconductivity: The state in which a material has zero electrical resistance and expels magnetic fields below a critical temperature. The defining phenomenon observed in yttrium barium copper oxide is superconductivity.
Perovskite: A crystal structure with the general formula ABX₃, often adopted by oxides and related materials. Yttrium barium copper oxide has a distorted, layered structure related to perovskite building blocks.
Oxygen stoichiometry: The proportion of oxygen atoms in a material relative to its chemical formula. Changing δ alters carrier concentration and can switch YBa₂Cu₃O₇−δ between superconducting and nonsuperconducting states.
Second-generation superconducting wire: A coated conductor made by depositing a thin superconducting layer on a flexible metal substrate. YBa₂Cu₃O₇−δ is the superconducting layer used in many coated-conductor designs.
Bednorz–Müller discovery: The 1986 discovery of superconductivity in a lanthanum-barium-copper oxide ceramic by J. Georg Bednorz and K. Alex Müller. Their result prompted the search that soon produced superconducting yttrium barium copper oxide.
Orthorhombic crystal system: A crystal system with three unequal axes meeting at right angles. Oxygen-rich YBa₂Cu₃O₇−δ commonly has this symmetry, unlike its oxygen-poor tetragonal form.
CuO₂ plane: A sheet of copper and oxygen atoms found in cuprate crystal structures. Superconducting charge transport is concentrated in these planes within the crystal.
Liquid nitrogen: Nitrogen cooled into a liquid near 77 kelvin at atmospheric pressure. Its temperature is below the material’s transition temperature, enabling comparatively accessible cooling.

Linked from 3 pages