LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 7 of total 7

Search options

  1. Article: Percolation Magnetism in Ferroelectric Nanoparticles.

    Golovina, Iryna S / Lemishko, Serhii V / Morozovska, Anna N

    Nanoscale research letters

    2017  Volume 12, Issue 1, Page(s) 382

    Abstract: Nanoparticles of potassium tantalate ( ... ...

    Abstract Nanoparticles of potassium tantalate (KTaO
    Language English
    Publishing date 2017-06-02
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2253244-4
    ISSN 1556-276X ; 1931-7573
    ISSN (online) 1556-276X
    ISSN 1931-7573
    DOI 10.1186/s11671-017-2146-1
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article ; Online: Formation of BiFeO

    Plokhikh, Aleksandr V / Falmbigl, Matthias / Golovina, Iryna S / Akbashev, Andrew R / Karateev, Igor A / Presnyakov, Mikhail Y / Vasiliev, Alexander L / Spanier, Jonathan E

    Chemphyschem : a European journal of chemical physics and physical chemistry

    2017  Volume 18, Issue 15, Page(s) 1966–1970

    Abstract: We report on the growth of polycrystalline ... ...

    Abstract We report on the growth of polycrystalline BiFeO
    Language English
    Publishing date 2017-08-05
    Publishing country Germany
    Document type Journal Article
    ISSN 1439-7641
    ISSN (online) 1439-7641
    DOI 10.1002/cphc.201700407
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Article ; Online: Evidence of extended cation solubility in atomic layer deposited nanocrystalline BaTiO

    Falmbigl, Matthias / Karateev, Igor A / Golovina, Iryna S / Plokhikh, Aleksandr V / Parker, Thomas C / Vasiliev, Alexander L / Spanier, Jonathan E

    Nanoscale

    2018  Volume 10, Issue 26, Page(s) 12515–12525

    Abstract: Thin films of ≈50 nm thickness with Ba/Ti-ratios ranging from 0.8 to 1.06 were prepared by depositing alternating layers of Ba(OH)2 and TiO2. Annealing at 750 °C promoted the solid-solid transformation into polycrystalline BaTiO3 films containing a ... ...

    Abstract Thin films of ≈50 nm thickness with Ba/Ti-ratios ranging from 0.8 to 1.06 were prepared by depositing alternating layers of Ba(OH)2 and TiO2. Annealing at 750 °C promoted the solid-solid transformation into polycrystalline BaTiO3 films containing a mixture of the perovskite and the hexagonal polymorphs with average crystallite sizes smaller than 14 nm and without impurity phases. This, together with an increase of the cubic lattice parameters for Ba-rich films, suggests an extended metastable solubility range for the perovskite-phase in these nanocrystalline thin films on both sides of the stoichiometric composition. Mapping of the cation distribution utilizing energy-filtered transmission electron microscopy corroborates defect accommodation within the BaTiO3 grains. While the cation off-stoichiometry in thermodynamic equilibrium is negligible for BaTiO3, the metastable extended solubility range in the thin films can be directly correlated to the low annealing temperature and nanocrystalline nature. The leakage current behavior can be explained by the formation of Schottky defects for nonstoichiometric films, and the cation ratio has a distinct impact on the dielectric properties: while excess-BaO has a marginal detrimental effect on the permittivity, the dielectric constant declines rapidly by more than 50% towards the Ti-rich side. The present findings highlight the importance of compositional control for the synthesis of nanocrystalline BaTiO3 thin films, in particular for low annealing and/or deposition temperatures. Our synthesis approach using alternating layers of Ba(OH)2 and TiO2 provides a route to precisely control the cation stoichiometry.
    Language English
    Publishing date 2018-07-09
    Publishing country England
    Document type Journal Article
    ZDB-ID 2515664-0
    ISSN 2040-3372 ; 2040-3364
    ISSN (online) 2040-3372
    ISSN 2040-3364
    DOI 10.1039/c8nr01176a
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  4. Article: Electromagnetic characterization of rectangular ferroelectric resonators.

    Geifman, Ilia / Golovina, Iryna S

    Journal of magnetic resonance (San Diego, Calif. : 1997)

    2005  Volume 174, Issue 2, Page(s) 292–300

    Abstract: ... electromagnetic field in the FR is computed and analyzed. The computations, based on solution of Maxwell's field ...

    Abstract An optimized geometry for a rectangular ferroelectric resonator (FR) is proposed to increase signal-to-noise ratio in EPR spectroscopy. To develop optimization criteria, the distribution of the microwave electromagnetic field in the FR is computed and analyzed. The computations, based on solution of Maxwell's field equations, were made for two types of rectangular FRs-a FR with a hollow sample hole and a FR with a blind sample hole. To introduce the samples, a hole was drilled through the resonator with its axis aligned to the axis of the FR. We computed and studied the spatial distributions of H- and E-components of the microwave electromagnetic field for two rectangular FRs, made of single-crystal potassium tantalate, with the following sizes: 1.9 x 1.9 x 1.4mm(3) and 1.7 x 1.7 x 3.1mm(3). As analysis of the obtained data indicated, in both resonators, the lowest mode was TE(11delta). By analyzing the distribution of the microwave field in the FR and comparing it with the experimental result, we developed optimization criteria for the geometry of a rectangular FR.
    Language English
    Publishing date 2005-06
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1469665-4
    ISSN 1096-0856 ; 1557-8968 ; 1090-7807 ; 0022-2364
    ISSN (online) 1096-0856 ; 1557-8968
    ISSN 1090-7807 ; 0022-2364
    DOI 10.1016/j.jmr.2005.02.017
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  5. Article ; Online: Controlling the phase transition in nanocrystalline ferroelectric thin films via cation ratio.

    Golovina, Iryna S / Falmbigl, Matthias / Hawley, Christopher J / Ruffino, Anthony J / Plokhikh, Aleksandr V / Karateev, Igor A / Parker, Thomas C / Gutierrez-Perez, Alejandro / Vasiliev, Alexandre L / Spanier, Jonathan E

    Nanoscale

    2018  Volume 10, Issue 46, Page(s) 21798–21808

    Abstract: Traditionally, the ferroelectric Curie temperature can be manipulated by chemical substitution, e.g., in Ba1-xSrxTiO3 as one of the archetypical representatives. Here, we show a novel approach to tune the ferroelectric phase transition applicable for ... ...

    Abstract Traditionally, the ferroelectric Curie temperature can be manipulated by chemical substitution, e.g., in Ba1-xSrxTiO3 as one of the archetypical representatives. Here, we show a novel approach to tune the ferroelectric phase transition applicable for nanostructured thin films. We demonstrate this effect in nano-grained BaTiO3 films. Based on an enhanced metastable cation solubility with Ba/Ti-ratios of 0.8 to 1.06, a significant shift of the phase transition temperature is discovered. The transition temperature increases linearly from 212 K to 350 K with increasing Ba/Ti ratio. For all Ba/Ti ratios, a completely diffused phase transition is present resulting in a negligible temperature sensitivity of the dielectric constant. Schottky defects are identified as the driving force behind the off-stoichiometry and the shift of the phase transition temperature as they locally induce lattice strain. Complementary temperature dependent Raman experiments reveal the presence of the hexagonal polymorph in addition to the perovskite phase in all cases. Interestingly, the hexagonal BaTiO3 influences the structural transformation on the Ba-rich side, while on the Ti-rich side no changes for the hexagonal polymorph at the ferroelectric transition temperature are observed. This concerted structural change of both polymorphs on the Ba-rich side causes a broad phase transition region spanning over a wide range up to 420 K including the transition temperature of 350 K obtained from dielectric measurements. These findings are promising for fine adjustment of the phase transition temperature and low temperature coefficient of permittivity.
    Language English
    Publishing date 2018-11-19
    Publishing country England
    Document type Journal Article
    ZDB-ID 2515664-0
    ISSN 2040-3372 ; 2040-3364
    ISSN (online) 2040-3372
    ISSN 2040-3364
    DOI 10.1039/c8nr06268d
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  6. Article ; Online: Novel multisample dielectric resonators for electron paramagnetic resonance spectroscopy.

    Golovina, Iryna S / Kolesnik, Sergiy P / Geifman, Ilia N / Belous, Anatoliy G

    The Review of scientific instruments

    2010  Volume 81, Issue 4, Page(s) 44702

    Abstract: We have developed and tested two types of novel dielectric resonators for simultaneous recording of electron paramagnetic resonance (EPR) spectra from two to four samples. The resonator of the first type contains two holes, and the other resonator ... ...

    Abstract We have developed and tested two types of novel dielectric resonators for simultaneous recording of electron paramagnetic resonance (EPR) spectra from two to four samples. The resonator of the first type contains two holes, and the other resonator contains four holes for introduction of the samples. Also, the resonator structure includes a pair of gradient coils. Dielectric resonators made of materials with high dielectric constant with low losses can be inserted into the standard EPR cavity or waveguide in the maximum microwave magnetic field. Gradient coils are located outside the cavity (or waveguide) so that their axes are parallel to the static magnetic field. Computer simulations were made to obtain microwave characteristics of the resonators such as resonant frequency, sizes, and distribution of the fields. Spacing of the point samples and optimum value of the magnetic-field gradient have been chosen correctly. The designed resonators can be applied in express analysis using EPR technique, for instance.
    Language English
    Publishing date 2010-04
    Publishing country United States
    Document type Journal Article
    ZDB-ID 209865-9
    ISSN 1089-7623 ; 0034-6748
    ISSN (online) 1089-7623
    ISSN 0034-6748
    DOI 10.1063/1.3378287
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Bonn / Germany

    Z 4' 46/112: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  7. Article ; Online: Dielectric microwave resonators in TE(011) cavities for electron paramagnetic resonance spectroscopy.

    Mett, Richard R / Sidabras, Jason W / Golovina, Iryna S / Hyde, James S

    The Review of scientific instruments

    2008  Volume 79, Issue 9, Page(s) 94702

    Abstract: ... those from a computer program that solves Maxwell's equations by finite element methods. Depending on the relative natural ...

    Abstract The coupled system of the microwave cylindrical TE(011) cavity and the TE(01delta) dielectric modes has been analyzed in order to determine the maximum achievable resonator efficiency parameter of a dielectric inserted into a cavity, and whether this value can exceed that of a dedicated TE(01delta) mode dielectric resonator. The frequency, Q value, and resonator efficiency parameter Lambda for each mode of the coupled system were calculated as the size of the dielectric was varied. Other output parameters include the relative field magnitudes and phases. Two modes are found: one with fields in the dielectric parallel to the fields in the cavity center and the other with antiparallel fields. Results closely match those from a computer program that solves Maxwell's equations by finite element methods. Depending on the relative natural resonance frequencies of the cavity and dielectric, one mode has a higher Q value and correspondingly lower Lambda than the other. The mode with the higher Q value is preferentially excited by a coupling iris or loop in or near the cavity wall. However, depending on the frequency separation between modes, either can be excited in this way. A relatively narrow optimum is found for the size of the insert that produces maximum signal for both modes simultaneously. It occurs when the self-resonance frequencies of the two resonators are nearly equal. The maximum signal is almost the same as that of the dedicated TE(01delta) mode dielectric resonator alone, Lambda congruent with40 G/W(1/2) at X-band for a KTaO(3) crystal. The cavity is analogous to the second stage of a two-stage coupler. In general, there is no electron paramagnetic resonance (EPR) signal benefit by use of a second stage. However, there is a benefit of convenience. A properly designed sample-mounted resonator inserted into a cavity can give EPR signals as large as what one would expect from the dielectric resonator alone.
    MeSH term(s) Computer Simulation ; Crystallization ; Electric Impedance ; Electromagnetic Fields ; Electron Spin Resonance Spectroscopy/instrumentation ; Equipment Design/instrumentation ; Finite Element Analysis ; Microwaves ; Oxides/chemistry ; Potassium/chemistry ; Tantalum/chemistry ; Temperature
    Chemical Substances Oxides ; potassium tantalate oxide ; Tantalum (6424HBN274) ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2008-11-27
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 209865-9
    ISSN 1089-7623 ; 0034-6748
    ISSN (online) 1089-7623
    ISSN 0034-6748
    DOI 10.1063/1.2976033
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Bonn / Germany

    Z 4' 46/112: Show issues

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top