Harrison et al. (Reports, 23 December 2005, p. 1947) proposed that plate tectonics and granites existed 4.5 billion years ago (Ga), within 70 million years of Earth's formation, based on geochemistry of >4.0 Ga detrital zircons from Australia. We highlight the large uncertainties of this claim and make the more moderate proposal that some crust formed by 4.4 Ga and oceans formed by 4.2 Ga.

The structure of triclinic disodium hafnium disilicate, Na2HfSi2O7, has been determined by laboratory powder X-ray diffraction and refined by the Rietveld refinement. The structure is a framework made of alternate layers of HfO6 octa-hedra and SiO4 tetra-hedra linked by common O atoms. Sodium atoms are located in the voids of the framework, aligned into tunnels along the [010] direction. Na2HfS...

Hafnium oxide layer was deposited on unheated silicon wafer and glass substrates at different power by using RF magnetron sputtering technique. The structural property investigated Raman spectroscopy. Moreover, HfO2 structure in monoclinic major phase especially high found from the spectra vibrational modes. In addition, oxidations state of hafnium thin films gained synchrotron-based X-ray abso...

Applying transmission Kikuchi diffraction (TKD) allows us to fundamentally investigate the Si-doped-hafnium-oxide (HSO) microstructure that results from interface layer present in ferroelectric field-effect transistors. In addition predominant orthorhombic phase, dendritic HSO grains larger than 100 nm govern composition. Furthermore, observed strong out-of-plane texture aligned along [110] and...