PAC study of the Si-HfO2 system subjected to high energy ball milling

CECILIA Y. CHAIN; LAURA C. DAMONTE; S.FERRARI; JORGE A. MARTINEZ; CLAUDIA E. RODRIGUEZ TORRES; ALBERTO F. PASQUEVICH

Ginebra

Conferencia; 3rd Joint Internacional Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole Interactions; 2010

Organización Europea para la Investigación Nuclear (CERN)

A wide band gap and a high dielectric constant make hafnia an excellent candidate to replace SiO2 in technological/electronic devices. In particular, mixtures hafnia/silicon or hafnia/silica could come up to the actual expectations of performance. The aim of this article is to characterize high-energy ball milled equimolar mixtures of HfO2 and crystalline silicon powder by Perturbed Angular Correlation (PAC) technique complemented with X-ray diffraction analyses. In order to better analyze the results of the milling treatments, pure hafnium oxide was milled in the same conditions and measured subsequently. PAC results from pure hafnium oxide reveal that the well-known monoclinic phase of HfO2 is strongly disrupted with 2 hours of high- energy ball milling. The damage does not increase so much as the milling treatment progresses. A new hyperfine interaction, rather asymmetric, must be proposed to give account of the experimental results. The structure of m-HfO2 is less perturbed in the milled mixtures HfO2-Si and HfO2-SiO2 if compared with the same milling times in pure HfO2. The same new interaction observed in milled HfO2, but more asymmetric and distributed, must be considered to give account of the experimental results. This interaction becomes predominant as the milling treatment progresses