Bi-2212 and Y123 highly curved single-crystal-like objects: whiskers, bows and ring-like structures

High-temperature superconducting objects of Bi2 Sr2 CaCu2 O8 and YBa2 Cu3 O7 highly curved in the ab-plane, such as curved/kinked whiskers, bows and ring-like structures, were obtained within a solid–liquid–solid (SLS) grass-like growth mechanism. As-grown objects are crystals with three-dimensional epitaxy similar to conventional single crystals: they can be viewed as crystal parts ‘cut’ from a conventional rectangular crystal. Between our curved objects and conventional crystals, whiskers or thin films there are some differences in the superconducting properties induced only by the shape factors and no new physics is observed. Some details of the growth mechanism are discussed, emphasizing curved-line formation.