The nature and the role of 1 to 5 nm thick TiO 2 seed layers for the growth of textured PbTiO 3 and Pb(Zr,Ti)O 3 thin films on textured Pt(111) thin film substrates have been studied. Under otherwise identical in situ sputter deposition process conditions, the PbTiO 3 texture could be turned from (100) to (111) orientation by adding the seed layer. This is demonstrated by patterning the TiO 2 film. Auger electron spectroscopy and x-ray photoemission spectroscopy showed that the seed layer was a continuous TiO 2 film. X-ray photoelectron diffraction measurements revealed epitaxial ordering in the seed layer. As there is no azimuthal order among the Pt grains, the reduced information of azimuthally averaged polar cuts is obtained. These give strong evidence for a strained rutile (110) structure. Various deposition experiments indicated that the TiO 2 is effective only when it is ordered before the PbTiO 3 nucleation starts. The epitaxial relationship between PbTiO 3 (111) and Pt(111) is thus mediated by the intermediate, epitaxial TiO 2 film, which is dissolved or transformed to PbTiO 3 afterwards. The observed growth behavior is discussed in terms of surface and interface energies.

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Anthropogenic and natural forest disturbance cause ecological damage and carbon emissions. Forest disturbance in the Amazon occurs in the form of deforestation (conversion of forest to non‐forest land covers), degradation from the extraction of forest resources, and destruction from natural events. The crucial role of the Amazon rainforest in the hydrologic cycle has even led to the speculation of a disturbance “tipping point” leading to a collapse of the tropical ecosystem. Here we use time series analysis of Landsat data to map deforestation, degradation, and natural disturbance in the Amazon Ecoregion from 1995 to 2017. The map was used to stratify the study area for selection of sample units that were assigned reference labels based on their land cover and disturbance history. An unbiased statistical estimator was applied to the sample of reference observations to obtain estimates of area and uncertainty at biennial time intervals. We show that degradation and natural disturbance, largely during periods of severe drought, have affected as much of the forest area in the Amazon Ecoregion as deforestation from 1995 to 2017. Consequently, an estimated 17% (1,036,800 ± 24,800 km2, 95% confidence interval) of the original forest area has been disturbed as of 2017. Our results suggest that the area of disturbed forest in the Amazon is 44%–60% more than previously realized, indicating an unaccounted for source of carbon emissions and pervasive damage to forest ecosystems.

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