coated conductor is the layered architecture of a practical high-temperature superconducting wire — a superconducting film a few micrometers thick grown onto a flexible metal ribbon through intermediate buffer layers and capped with silver and copper.
The term names a manufacturing method rather than a material. 📝REBCO is a brittle ceramic whose ability to carry current collapses unless its crystal grains are aligned in all three directions at once, so it cannot be melted, drawn, or extruded into wire the way niobium-titanium can. It has to be deposited. A high-strength nickel-alloy ribbon supplies the mechanical backbone; a stack of oxide buffer layers grown on it does two jobs at once, transferring a biaxial crystallographic texture upward to template the film and blocking chemical diffusion from the metal below; the REBCO film, typically one to three micrometers thick, grows on that template; and silver followed by electroplated copper caps the stack, giving current a low-resistance path to divert into wherever a spot of the ceramic goes normal.
The near-neighbor distinction is between the architecture and the product. 📝HTS tape is the finished ribbon a magnet is wound from; coated conductor names how that ribbon is built, and is used interchangeably with second-generation HTS wire — second against a first generation in which BSCCO powder was packed into silver tubes and drawn. The architecture also explains the conductor's characteristic behavior. Only a small fraction of the cross-section superconducts, so the engineering current density averaged over the whole tape falls far below the film's own 📝critical current density, and because that film is one wide unfilamented sheet rather than the bundle of fine filaments a 📝low-temperature superconductor is drawn into, it magnetizes strongly — the root of both the 📝screening current that distorts field quality and the 📝AC loss that loads the cryoplant in 📝High-Temperature Superconducting (HTS) Magnets. Making that stack reproducibly over kilometers is the industrial problem reported in 📝YBCO Wire Production for Fusion.