Atomic resolution and study of surface morphology of HgBaCuO single crystals by scanning probe methods

✍ Scribed by Hubler, U.; Hermann, B. A.; Lang, H. P.; Karpinski, J.; Güntherodt, H.-J.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 491 KB
• Volume: 27
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/(sici)1096-9918(199905/06)27:5/6<521::aid-sia520>3.0.co;2-f

✦ Synopsis

Superconducing

single crystals grown in an crucible using a high-pressure furnace (argon HgBa 2 CuO 4'x Al 2 O 3 pressure = 10.1 kbar) show a clean and smooth surface. Investigations by scanning tunnelling (STM), scanning force (SFM) and friction force (FFM) microscopies reveal an atomically Ñat surface with steps ¿4 nm high in the [ 001 ] direction. At the surface, particles are observed that may have been caused by ageing under ambient conditions. These particles exhibit a contrast reversal in FFM images, implying that they consist of a di †erent material than the underlying matrix. Occasionally, free step-Ñow during crystal growth is hindered by atomic point defects, resulting in local step bending. Such processes may explain the micrometre-sized indents found along the steps. On an atomic scale, STM measurements reveal an approximately square atomic lattice (a = 4.0-4.4 and an unex-A ) pected domain structure with edge dislocations and point defects.