| Autor: |
Yan, S. L., Fang, L., Aytug, T., Xie, Y. Y., Wu, J. Z., Siegal, M. P. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2/1/2003, Vol. 93 Issue 3, p1666, 6p, 1 Black and White Photograph, 6 Graphs |
| Abstrakt: |
Superconducting HgBa[sub 2]CaCu[sub 2]O[sub 6+δ] (Hg-1212) thin films were obtained from Tl[sub 2]Ba[sub 2]CaCu[sub 2]O[sub x] (Tl-2212) precursor films using a cation-exchange process. In this process, Tl cations on the precursor lattice were thermally excited and then replaced with Hg cations. The mechanism of such an atomic perturbation process has presented an interesting topic in material research. This work investigated the evolution of the crystalline structure and surface morphology of the film during such a conversion. It has been found that the Hg-1212 films may inherit epitaxy and surface morphology from their Tl[sub 2]Ba[sub 2]CaCu[sub 2]O[sub x] precursor films at the low perturbation energy limit. Although the c-axis lattice constant was reduced from 1.48 nm for Tl-2212 to 1.27 nm for Hg-1212 during the cation exchange, the in-plane texture of the film remains. The inverse conversion from Hg-1212 to Tl-2212 has also been investigated. Hg-1212 is found to be energetically preferred so that a perturbation above a threshold is required to convert it back to Tl-2212. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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