Magnetic Nanocomposites Based on Opal Matrices

2018 ◽  
Vol 781 ◽  
pp. 149-154 ◽  
Author(s):  
Alexey Belyanin ◽  
Alexander Bagdasarian ◽  
Sergey Bagdasarian ◽  
Petr Luchnikov ◽  
Natalya Katakhova
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Constant ◽  
Hysteresis Loops ◽  
Lattice Packing ◽  
Magnetic Nanocomposites ◽  
Multiferroic Materials ◽  
X Ray ◽  
Temperature Range ◽  
Frequency Dependences

Features of obtaining magnetic nanocomposites based on the lattice packing of SiO2 nanoscale (opal matrices) with clusters of multiferroic materials (Li-Zn, Bi, Fe, Dy, Gd and Yb titanates) in their interstitial cavities have been considered. For magnetic nanocomposites creation opal matrices with SiO2 nanoscale of ~ 260 nm in diameter have been used. The composition of nanocomposites has been also studied using X-ray diffractometry and Raman spectroscopy. The results of the frequency dependences measurement for the dielectric constant of the nanostructures obtained have been presented. Hysteresis loops have been examined for the samples obtained in the temperature range from 2 to 400 K.

scholarly journals PREPARATION AND PHYSICAL PROPERTIES OF OPAL MATRICES WITH NANOPARTICLES OF TITANIUM AND IRON OXIDES

2016 ◽  
Vol 11 (6) ◽  
pp. 91-97
Author(s):  
M. I. Samoylovich ◽  
А. F. Belyanin ◽  
A. S. Bagdasaryan
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Hysteresis Loops ◽  
X Ray Diffraction ◽  
Iron Compounds ◽  
Dielectric Characteristics ◽  
X Ray ◽  
Composition And Structure ◽  
Synthesized Materials ◽  
Frequency Dependences

The article considers specific features of the formation of nanocomposites based on the lattice packing of SiO2 nanospheres (opal matrices) with clusters of titanium and iron compounds (FeTiO3, FeTi2O5, TiO2, Fe2O3) embedded into nanopores between spheres. For the formation of the nanocomposites samples of opal matrices with the sizes of single-domain regions > 0.1 mm3 were used. The diameter of the SiO2 nanospheres was ~260 nm. Nanocomposites with the volume > 1 cm3 and 10-15% of interspherical nanospacing filled by crystallites of titanium and iron compounds were obtained. The composition and structure of the nanocomposites were studied by electron microscopy, X-ray diffraction and Raman spectroscopy. The dependence of the composition of the synthesized materials on the conditions of their preparation is shown. Results of measurements of the frequency dependences (within the range 1 MHz - 3 GHz) of the magnetic and dielectric characteristics of the obtained nanostructures are presented. Hysteresis loops were studied for the obtained samples.

scholarly journals Dielectric properties of Bi12SiO20 crystals doped with Al

2019 ◽  
Vol 27 (2) ◽  
pp. 85-88
Author(s):  
T. V. Panchenko ◽  
L. M. Karpova
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Hysteresis Loops ◽  
Complex Dielectric Permittivity ◽  
Temperature Range ◽  
Dielectric Matrix ◽  
Before And After ◽  
Frequency Dependences

The temperature-frequency dependences of the complex dielectric permittivity ε and the voltage-farad characteristics of undoped and aluminum doped Bi12SiO20 crystals are studied before and after their polarization. It is shown that Al ions in the Bi12SiO20 dielectric matrix provide a significant increase as well as nonlinearity of ε in the temperature range 300 – 800 K and electric field strengths Е = 103 – 104 V/cm. It is shown that polarization causes the appearance of dielectric hysteresis loops. Al impurity significantly affects the appearance and parameters of these loops. The role of Al ions in increasing the contribution of the quasi-dipole mechanism in the polarization processes is revealed.

The Dependence of Dielectric Properties on Composition Variation in Ba0.6Sr0.4(YTa)yTi1-2yO3

2002 ◽  
Vol 720 ◽  
Author(s):  
Daniel Potrepka ◽  
Steven Tidrow ◽  
Arthur Tauber ◽  
Kevin Kirchner ◽  
Matthew Ervin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric ◽  
Composition Variation ◽  
Device Applications ◽  
Improved Performance

AbstractBa0.6Sr0.4(YTa)yTi1-2yO3 has been shown to have properties which are promising for tunable applications requiring low dielectric constant [1]. Ba0.6Sr0.4(YTa)yTi1-2yO3 with y ≤ 0.10 has been synthesized and well-characterized using x-ray diffraction, EDAX, and Raman Spectroscopy. The dependence of the dielectric properties on concentration, y, of Y and Ta are discussed along with implications for improved performance in device applications.

Ferroelectric BaTiO3/BaZrO3 superlattices: X-ray diffraction, Raman spectroscopy, and polarization hysteresis loops

2010 ◽  
Vol 108 (8) ◽  
pp. 084104 ◽  
Author(s):  
M. El Marssi ◽  
Y. Gagou ◽  
J. Belhadi ◽  
F. De Guerville ◽  
Yu. I. Yuzyuk ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Hysteresis Loops ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals STRUCTURE AND DIELECTRIC PROPERTIES OF NANOCOMPOSITES: OPAL MATRIX - TITANIUM OXIDE AND RARE-EARTH TITANATES

2016 ◽  
Vol 11 (2) ◽  
pp. 66-73 ◽  
Author(s):  
M. I. Samoylovich ◽  
А. F. Belyanin ◽  
A. S. Bagdasaryan ◽  
V. .. Bovtun
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Rare Earth ◽  
Titanium Oxide ◽  
Opal Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composition And Structure ◽  
Lattice Packings ◽  
Frequency Dependences

The conditions for the formation of nanocomposites based on the basis of lattice packings SiO2 nanospheres (opal matrices) with included clusters of crystalline phase of titanium oxide (TiO2 and TiO) and rare-earth titanates of the general formula R2TiO5 or R2Ti2O7, where R - Er, Dy, Gd, Pr, Tb and Yb in interspherical nanospacing are considered. The composition and structure of the nanocomposites studied electron microscopy, X-ray diffraction and Raman spectroscopy. Results of measuring of the frequency dependences of real and imaginary components of the permittivity and microwave conductivity (ranging 10-2-1012 Hz) obtained nanostructures are viewed.

scholarly journals Структура и диэлектрические свойства наноструктурированной керамики Bi-=SUB=-1-x-=/SUB=-Sm-=SUB=-x-=/SUB=-FeO-=SUB=-3-=/SUB=-

2019 ◽  
Vol 61 (11) ◽  
pp. 2097
Author(s):  
С.А. Садыков ◽  
Н.М-Р. Алиханов ◽  
С.Н. Каллаев ◽  
М.Х. Рабаданов ◽  
Д.К. Палчаев ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Phase Transformations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Two Phases ◽  
Nanostructured Sample

The structure and dielectric properties of polycrystalline multiferroics of the Bi1-xSmxFeO3 system (x = 0-0.2) are investigated. X-ray diffraction revealed that two phases coexist in the x = 0.1 nanostructured sample: rhombohedral R3c and orthorhombic Pbam. On the temperature dependences of the dielectric constant ε'(T), four anomalies characteristic of phase transformations were found in the temperature range of ~ 180°С, ~ 250°С, ~ 300°С and TN ~ 350°С. It is shown that with increasing samarium concentration, the dielectric constant ε' increases, and tgδ decreases

scholarly journals Comparison of Electronic Structure and Magnetic Properties of Few Layer Graphene and Multiwall Carbon Nanotubes

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Sekhar Chandra Ray
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Multiwall Carbon Nanotubes ◽  
Hysteresis Loops ◽  
Structural Defects ◽  
X Ray ◽  
Layer Graphene ◽  
Few Layer Graphene ◽  
Multiwall Carbon

A comparative study has been made for the non-catalyst based few layer graphene (FLG) and Fe-catalyst based multiwall carbon nanotubes (MWCNTs). Magnetic and electronic properties of FLG and MWCNTs were studied using magnetic M-H hysteresis loops and synchrotron radiation based X-ray absorption fine structure spectroscopy measurements. Structural defects and electronic and bonding properties of FLG/MWCNTs have been studied using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). The work functions of FLG and MWCNTs are 4.01 eV and 3.79 eV, respectively, obtained from UPS (He-I) spectra. UPS (He-II) results suggest that the density of states (DOS) of MWCNTs is higher than FLG and is consistent with Raman spectroscopy result that shows the defect of MWCNTs is higher than FLG. The magnetic coercivity (Hc) of the MWCNTs (~750 Oe) is higher than FLG (~85 Oe) which could be used for various technological magnetic applications.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray
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