ISSN:
1572-9540
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Using the 93.31 keV Mössbauer 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 Mössbauer 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 Å can lead to such enhancedη parameters. The Lamb-Mössbauer factorf drastically drops when the particle size is reduced below ∼ 10 nm. Two lattice-dynamic models are discussed which successfully describe this behavior.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02146317