14 research outputs found

    Water Supply Planning: Middle Illinois Progress Report

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    This report presents a summary of 1) the technical information assembled to describe existing water availability and sources of supply within the 7-county (LaSalle, Livingston, Marshall, Peoria, Putnam, Stark, and Woodford Counties) Middle Illinois River Region in central Illinois (Figures 1 and 2) and 2) the development of preliminary computer models that will be used in future studies to estimate impacts to water availability resulting from future water development in the region. Through funding by the Illinois Department of Natural Resources (IDNR), the Illinois State Water Survey (ISWS) and Illinois State Geological Survey (ISGS) prepared this document for the Middle Illinois Regional Water Supply Planning Committee (MIRWSPC) to aid in the development of a plan for meeting the future growth of water supply demands within the basin to the year 2060. It contains background information to provide an overview of management criteria and an understanding of the constraints and policies used in conducting analyses and making decisions concerning water usage. Models will be applied to a broad range of conditions, including a set of selected future water use scenarios to more fully characterize water availability within the Middle Illinois River Region to the year 2060. In addition, as the MIRWSPC deliberates and prepares its water supply planning document, the information presented in this report will be reviewed and, in some cases, additional analysis may be performed and results revised. A more complete reporting of the model development, the results of the scenario simulations, and subsequent work concerning water availability will be published at the end of that forthcoming study. The existing technical information compiled as the first task of this study includes a review of previous analyses and publications dealing with the Middle Illinois River Region’s water resources; collection of hydrogeological and hydrologic data, primarily as needed for modeling; and, in certain cases, additional analyses of that data, such as data mining of well records and yield analyses of surface water supply sources. This compiled information focuses on the three primary sources of water supply within the Middle Illinois River watershed: 1) direct withdrawals from the Illinois River; 2) public supply systems using the Vermilion River and off-channel reservoirs at Pontiac and Streator; and 3) groundwater from within the Middle Illinois River basin. A companion report has been published (Meyer et al., In preparation) evaluating water demand scenarios out to 2060 for the Middle Illinois River, Northwest Illinois, and Kankakee River Regions.published or submitted for publicationis peer reviewedOpe

    Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

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    Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry

    Origin and dynamics of umbrella states in rare-earth iron garnets

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    Rare-earth iron garnets R3R_{3}Fe5_{5}O12_{12} are fascinating insulators with very diverse magnetic phases. Their strong potential in spintronic devices has encouraged a renewal of interest in the study of their low temperature spin structures and spin wave dynamics. A striking feature of rare-earth garnets with RR-ions exhibiting strong crystal-field effects like Tb-, Dy-, Ho-, and Er-ions is the observation of low-temperature non-collinear magnetic structures featuring ``umbrella-like'' arrangements of the rare-earth magnetic moments. In this study, we demonstrate that such umbrella-like spin structures are naturally emerging from the crystal-field anisotropies of the rare-earth ions. By means of a general model endowed with only the necessary elements from the crystal structure, we show how umbrella-like spin structures can take place and calculate the canting-angle as a result of the competition between the exchange-interaction of the rare-earth and the iron ions as well as the crystal-field anisotropy. Our results are compared to experimental data, and a study of the polarised spin wave dynamics is presented. Our study improves the understanding of ``umbrella-like'' spin structures and paves the way for more complex spin wave calculations in rare-earth iron garnets with non-collinear magnetic phases.Comment: 8 pages, 7 figure

    Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

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    Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a La0.67Sr0.33MnO3/Hf0.5Zr0.5O2 capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction. When the top electrode is oxygen reactive, we observe reversible oxygen vacancy migration with electrodes as the source and sink of oxygen and the dielectric layer acting as a fast conduit at millisecond time scales. With nonreactive top electrodes and at longer time scales (seconds), the dielectric layer also acts as an oxygen source and sink. Our results show that ferroelectricity in hafnia-based thin films is unmistakably intertwined with oxygen voltammetry

    Polarisation Development at the European Spallation Source

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    To meet the ever-increasing user demand, eleven of the fifteen European Spallation Source (ESS) instruments under construction aim to offer polarised neutrons for user experiments. They include an imaging instrument, a SANS instruments, two reflectometers, three diffractometers, and four spectrometers. In conjunction with in-kind contributions and instrumentation grants, the ESS Polarisation Project will support the incorporation of polarisation analysis on eight of the eleven instruments. The project aims to deliver polarised neutrons for first-science experiments as instruments enter operation. Different polariser and polarisation analyser techniques will be available to accommodate the specifics of experiments on a given instrument. Polarised 3He neutron spin filter using either Metastable Optical Pumping (MEOP) or Spin-Exchange Optical Pumping (SEOP) techniques will provide shared-use equipment among many instruments, with SEOP’s main application being in situ beam-polarisation. Several instruments will also use polarising-supermirror devices. To provide wide-bandwidth spin-flipping capability to the time-of-flight instruments, Adiabatic Fast Passage (AFP) neutron spin flippers, also known as gradient-field radiofrequency spin flippers will be the main method of choice. Devices based on the same AFP principle will also be used to flip 3He nuclear spins. We are constructing our first 3He polariser setup, including field coils to produce highly uniform magnetic field. Monte Carlo simulations are being done for the supermirror polarisers. To ensure science-focused development, we are working with university partners in doing scientific experiments with polarised neutrons. These are some of the activities developing polarisation analysis for ESS instruments in our project

    Dataset: Reversible oxygen migration and phase transitions in hafnia-based ferroelectric devices

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    Unconventional ferroelectricity, robust at reduced nanoscale sizes, exhibited by hafnia-based thin-films presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. Here, we investigate epitaxial Hf0.5Zr0.5O2(HZO) capacitors, interfaced with oxygen conducting metals (La0.67Sr0.33MnO3, LSMO) as electrodes, using atomic resolution electron microscopy while in situelectrical biasing. By direct oxygen imaging, we observe reversible oxygen vacancy migration from the bottom to the top electrode through HZO and reveal associated reversible structural phase transitions in the epitaxial LSMO and HZO layers. We follow the phase transition pathways at the atomic scale and identify that these mechanisms are at play both in tunnel junctions and ferroelectric capacitors switched with sub-millisecond pulses. Our results unmistakably demonstrate that oxygen voltammetry and polarization switching are intertwined in these materials
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