Crystalline instability of Bi-2212 superconducting whiskers near room temperature

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2009-05, Vol.95 (2), p.479-484
• Main Authors: Cagliero, Stefano, Agostino, Angelo, Khan, Mohammad Mizanur Rahman, Truccato, Marco, Orsini, Francesco, Marinone, Massimo, Poletti, Giulio, Lascialfari, Alessandro
• Format: Article
• Language: English
• Subjects: Annealing; ANNEALING PROCESSES; Arrays; Atomic force microscopy; Bi-based cuprates; BISMUTH OXIDE; Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; COPPER OXIDE; CRYSTAL STRUCTURE; Cuprates superconductors (high tc and insulating parent compounds); Exact sciences and technology; Inorganic compounds; Instability; Machines; Manufacturing; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Stability; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Superconductivity; SUPERCONDUCTORS; Surface layer; Surfaces and Interfaces; Texture; TEXTURES; Thin Films; WHISKERS
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-008-4919-y

We report new evidences for the thermodynamic instability of whisker crystals in the Bi–Sr–Ca–Cu–O (BSCCO) system. Annealing treatments at 90°C have been performed on two sets of samples, which were monitored by means of X-Rays Diffraction (XRD) and Atomic Force Microscopy (AFM) measurements, respectively. Two main crystalline domains of Bi 2 Sr 2 CuCa 2 O 8+ x (Bi-2212) were identified in the samples by the XRD data, which underwent an evident crystalline segregation after about 60 hours. Very fast dynamics of the surface modifications was also described by the AFM monitoring. Two typologies of surface structures formed after about 3 annealing hours: continuous arrays of dome shaped bodies were observed along the edges of the whiskers, while in the central regions a dense texture of flat bodies was found. These modifications are described in terms of the formation of simple oxide clusters involving a degradation of the internal layers.