44 research outputs found

    SULFUR REDUCTION FROM CARBONATE-SULFATE MELT

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    Local Piezoelectric Properties of Doped Biomolecular Crystals

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    Piezoelectricity is the ability of certain crystals to generate mechanical strain proportional to an external electric field. Though many biomolecular crystals contain polar molecules, they are frequently centrosymmetric, signifying that the dipole moments of constituent molecules cancel each other. However, piezoelectricity can be induced by stereospecific doping leading to symme-try reduction. Here, we applied piezoresponse force microscopy (PFM), highly sensitive to local piezoelectricity, to characterize( 010) faces of a popular biomolecular material, α-glycine, doped with other amino acids such as L-alanine and L-threonine as well as co-doped with both. We show that, while apparent vertical piezoresponse is prone to parasitic electrostatic effects, shear piezoelectric activity is strongly affected by doping. Undoped α-glycine shows no shear piezoelectric response at all. The shear response of the L-alanine doped crystals is much larger than those of the L-threonine doped crystals and co-doped crystals. These observations are rationalized in terms of host–guest molecule interactions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research (RFBR), grant № 3-16492, and directly by the RFBR (grant № 19-52-06004 MNTI_a). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU was used. A.K. acknowledges the Ministry of Science and Higher Education of the Russian Federation for the support under the project № 075-15-2021-588 from 1.06.2021. The work was also developed within the scope of the project CICECO at the Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. I.L. expresses his gratitude to the Estate of Olga Klein–Astrachan fund, grant № 721977

    Piezoelectic properties of DL-alanine single crystals

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    The study was carried out using the equipment of UCSU "Modern Nanotechnology" UrFU with the financial support of the Government of the Russian Federation (Act 211, contract 02.A03.21.0006)

    Surface piezoelectricity and pyroelectricity in centrosymmetric materials: A case of α-glycine

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    Surface pyroelectricity and piezoelectricity induced by water incorporation during growth in α-glycine were investigated. Using the periodic temperature change technique, we have determined the thickness (~280 µm) of the near surface layer (NSL) and its pyroelectric coefficient (160 pC/(K × cm2) at 23◦C) independently. The thickness of NSL remains nearly constant till 60◦C and the pyroelectric effect vanishes abruptly by 70◦C. The piezoelectric effect, 0.1 pm/V at 23◦C measured with an interferometer, followed the same temperature dependence as the pyroelectric effect. Abrupt disappearance of both effects at 70◦C is irreversible and suggests that water incorporation to α-glycine forms a well defined near surface phase, which is different form α-glycine because it is polar but it too close to α-glycine to be distinguished by X-ray diffraction (XRD). The secondary pyroelectric effect was found to be <14% of the total, which is unexpectedly small for a material with a large thermal expansion coefficient. This implies that water incorporation infers minimal distortions in the host lattice. This finding suggests a path for the control of the piezoelectric and pyroelectric effects of the crystals using stereospecific incorporation of the guest molecules. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research, grant № 3-16492. This research was made possible in part by RFBR (Grant No. 19-52-06004 MNTI_a), and the Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under Project № 3.9534.2017/8.9. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU was used. I.L. expresses his gratitude to Estate of Olga Klein–Astrachan fund, grant № 721977

    Piezoelectric properties of α-glycine and DL-alanine single crystals

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    We present the results of studying piezoelectric properties in pure DL-alanine and α-glycine crystals doped with amino acids: L-alanine, L-serine, and phase transformations in pure DL-alanine crystals. Crystals were provided by Weizmann Institute of Science. Piezoelectric properties have been measured with high spatial resolution by piezoresponse force microscopy (PFM) using Asylum MFP 3D (Asylum Research, USA). Phase transformation was visualized by PFM

    Engineering of Pyroelectric Crystals Decoupled from Piezoelectricity as Illustrated by Doped α-Glycine

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    Design of pyroelectric crystals decoupled from piezoelectricity is not only a topic of scientific curiosity but also demonstrates effects in principle that have the potential to be technologically advantageous. Here we report a new method for the design of such materials. Thus, the co-doping of centrosymmetric crystals with tailor-made guest molecules, as illustrated by the doping of α-glycine with different amino acids (Threonine, Alanine and Serine). The polarization of those crystals displays two distinct contributions, one arising from the difference in dipole moments between guest and host and the other from the displacement of host molecules from their symmetry-related positions. These contributions exhibit different temperature dependences and response to mechanical deformation. Thus, providing a proof of concept for the ability to design pyroelectric materials with reduced piezoelectric coefficient (d22) to a minimal value, below the resolution limit of the method (<0.005 pm/V). © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.CICECO-Aveiro Institute of MaterialsIsraeli Ministry of Science with the Russian Foundation for Basic ResearchFundação para a Ciência e a Tecnologia, FCTRussian Foundation for Basic Research, РФФИ, (19‐52‐06004 MHTИ_a, 3‐16492)Israel Science Foundation, ISF, (1898/22)Ministerstwo Edukacji i Nauki, MNiSW, (N 075‐15‐2021‐677, UIDB/50011/2020, UIDP/50011/2020)Ural Federal University, UrFUMinistry of Science and Higher Education of the Russian Federation, (FEUZ-2020-0054)Funding text 1: This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research (RFBR), grant #3‐16492. Russian partners thank RFBR for the financial support within the project #19‐52‐06004 MHTИ_a. The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg. N 2968) was used with the financial support of the Ministry of Science and Higher Education of the RF (Project N 075‐15‐2021‐677). This work was developed within the scope of project CICECO‐Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020) financed by national funds through the FCT—Foundation for Science and Technology (Portugal). IL thank the Israel Science Foundation for the financial support (#1898/22). The research made possible due to historic generosity of the Harold Perlman Family. VS is grateful for financial support of the Ministry of Science Higher Education of the Russian Federation (state task FEUZ‐2020‐0054). o oFunding text 2: This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research (RFBR), grant #3-16492. Russian partners thank RFBR for the financial support within the project #19-52-06004 MHTИ_a. The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg. No 2968) was used with the financial support of the Ministry of Science and Higher Education of the RF (Project No 075-15-2021-677). This work was developed within the scope of project CICECO-Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020) financed by national funds through the FCT—Foundation for Science and Technology (Portugal). IL thank the Israel Science Foundation for the financial support (#1898/22). The research made possible due to historic generosity of the Harold Perlman Family. VS is grateful for financial support of the Ministry of Science Higher Education of the Russian Federation (state task FEUZ-2020-0054)

    Electrostriction measurements in gadolinium doped cerium oxide

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    The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU was used. The research was made possible with the financial support of Russian Foundation for Basic Research grant (15-52-06006-MNTI_a)
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