ISSN:
1432-0630
Keywords:
PACS: 61.16.Ch; 74.50.+r
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
2 Cu3O7-δ (YBCO) single crystals grown in BaZrO3 crucibles by scanning and friction force microscopy (SFM, FFM) as well as by scanning tunneling microscopy (STM) and angle resolved X-ray photo-electron spectroscopy (ARXPS). By STM and SFM, clean stepped terraces are observed on as-grown crystals. Friction contrast, however, implies the presence of different materials, presumably traces of flux. After oxidation of the YBCO crystals, particles of 10 to 100 nm in size appear on the surface. Their number per unit area increases with time when the crystal is stored in air. Complementary information on such aged YBCO surfaces is provided by ARXPS. These data reveal 3 nm of mainly BaCO3 and CuO on top of the YBCO matrix and suggest a very slow aging rate of the crystals, which is 20 times slower than for epitaxial thin films. The superconducting energy gap has been determined on fresh crystals by scanning tunneling spectroscopy (STS) at 4.6 K as 2Δ≈30 meV. By spatially resolved tunneling spectroscopy the vortex lattice in a magnetic field of 4 T has been imaged. The inter-vortex distance amounts to 20±2 nm.
Type of Medium:
Electronic Resource
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