Spin fluctuations in the quasi-two dimensional Heisenberg ferromagnet GdI_2 studied by Electron Spin Resonance

The spin dynamics of GdI_2 have been investigated by ESR spectroscopy. The temperature dependences of the resonance field and ESR intensity are well described by the model for the spin susceptibility proposed by Eremin et al. [Phys. Rev. B 64, 064425 (2001)]. The temperature dependence of the resonance linewidth shows a maximum similar to the electrical resistance and is discussed in terms of scattering processes between conduction electrons and localized spins.Comment: to be published in PR

PROPERTIES OF EPITAXIAL Si FILMS GROWN ON YTTRIA-STABILIZED CUBIC ZIRCONIA SUBSTRATES BY CHEMICAL VAPOR DEPOSITI ON

Epitaxial growth of single-crystal Si films on monocrystalline yttria-stabilized cubic zirconia, (Y2O3)m (ZrO2)1-m substrates with m=0.09 - 0.33 has been realized for the first time by the pyrolysis of SiH4 in H2 carrier gas. Films and substrates were characterized by means of Nomarski optical and scanning electron microscopies, reflection electron diffraction, MeV4He+ Rutherford backscattering and channeling, X-ray diffraction, transmission electron microscopy (TEM), secondary ion mass spectrometry, and electrical measurements. Single-crystal film growth was achieved on the three principal substrate cubic planes (100), (110), and (111) in the temperature range 975-1077°C at deposition rates of 0.08 - 1.2µm/ min. The orientations of the Si films were found to be the same as those of the substrates. The nearsurface crystal quality of several 0.4µm thick, (100) oriented Si films on yttria - stabilized zirconia was found by MeV He+ channeling and TEM to be superior to that of commercial (100) Si on sapphire films of similar thickness. The electrical properties of nominally undoped films were found to depend critically on the pre-deposition, in-situ substrate preparation. The effect of the ionic superconduction properties of the substrate material on the structure of the deposited Si films will also be discussed

How well do ecosystem indicators communicate the effects of anthropogenic eutrophication?

Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European assessment of eutrophication symptoms. Here we summarize responses to nutrient enrichment in Europe's seas, comparing existing time-series of selected pelagic (phytoplankton biomass and community composition, turbidity, N:P ratio) and benthic (macro flora and faunal communities, bottom oxygen condition) indicators based on their effectiveness in assessing eutrophication effects. Our results suggest that the Black Sea and Northern Adriatic appear to be recovering from eutrophication due to economic reorganization in the Black Sea catchment and nutrient abatement measures in the case of the Northern Adriatic. The Baltic is most strongly impacted by eutrophication due to its limited exchange and the prevalence of nutrient recycling. Eutrophication in the North Sea is primarily a coastal problem, but may be exacerbated by climatic changes. Indicator interpretation is strongly dependent on sea-specific knowledge of ecosystem characteristics, and no single indicator can be employed to adequately compare eutrophication state between European seas. Communicating eutrophication-related information to policy-makers could be facilitated through the use of consistent indicator selection and monitoring methodologies across European seas. This work is discussed in the context of the European Commission's recently published Marine Strategy Directive. © 2009 Elsevier Ltd. All rights reserved