67Zn-Mössbauer study of nanostructured ZnO
| Autor: | H. Gleiter, W. Potzel, T. P. Das, G. McMahon, G. M. Kalvius, H. Karzel, D. W. Mitchell, M. Steiner, U. Hiller, W. Schiessl |
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| Rok vydání: | 1995 |
| Předmět: |
Nuclear and High Energy Physics
Materials science Analytical chemistry Condensed Matter Physics Atomic and Molecular Physics and Optics Nanocrystalline material Condensed Matter::Materials Science Crystallography Nanocrystal Mössbauer spectroscopy Sublimation (phase transition) Particle size Physical and Theoretical Chemistry Single crystal Hyperfine structure Wurtzite crystal structure |
| Zdroj: | Hyperfine Interactions. 95:247-255 |
| ISSN: | 1572-9540 |
| DOI: | 10.1007/bf02146317 |
| Popis: | Using the 93.31 keV Mossbauer transition in67Zn we have investigated hyperfine interactions and lattice-dynamic effects of nanostructured hexagonal (wurtzite) ZnO. The nanocrystals with particle sizes between 3 and 30 ran were produced by a reactive-gas sublimation method and were subsequently compacted into solid bodies under external pressure. The nanocrystalline materials were used as sources in Mossbauer emission experiments. A drastic increase of the asymmetry parameter was found fromη=0 (single crystal) toη≈0.5 (nanostructured material). Our theoretical Hartree-Fock cluster calculations show that displacements of the Zn atoms off the hexagonal symmetry axis as small as 0.005 A can lead to such enhancedη parameters. The Lamb-Mossbauer factorf drastically drops when the particle size is reduced below ∼ 10 nm. Two lattice-dynamic models are discussed which successfully describe this behavior. |
| Databáze: | OpenAIRE |
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