Effect of low temperature short time annealing on oxygen content and surface quality of Bi2Sr2CaCu2O8 + δ single crystals

✍ Scribed by P. Kumar; B. Kumar; D.N. Kumar; G.K. Chadha

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 533 KB
• Volume: 411
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2004.07.008

✦ Synopsis

High temperature superconducting single crystals of 2212 phase of Bi-system have been grown by self-flux technique. They are annealed in different gas atmospheres of O 2 , N 2 and Ar to obtain overdoped and underdoped samples. Both time as well as temperature of the annealing has been optimized to get different T c -value in the range of 81-94 K. The oxygen contents d for overdoped and underdoped crystals have been precisely determined by iodometric titration technique. The change in T c and DT c have been discussed in terms of change in O-value in as-grown as well as in the optimally annealed crystals due to in-and out-diffusion of oxygen. The effect of annealing on surface morphology and defects features like growth steps, slip lines/bands and etch pits have also been studied by scanning electron microscopy.