scholarly journals Análisis cristalográfico, morfológico, eléctrico, óptico y magnético del nuevo material Dy2BiFeO6

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Jairo Roa-Rojas
Keyword(s):  
Dielectric Constant ◽  
Energy Gap ◽  
Magnetic Hysteresis ◽  
Magnetic Ordering ◽  
Relative Dielectric Constant ◽  
Double Perovskite ◽  
Crystallographic Analysis ◽  
Weiss Temperature ◽  
Constant E ◽  
Diffraction Patterns

We report structural analysis, surface morphology, magnetic ordering, dielectric response, optical feature and the electronic structure of the Dy2BiFeO6 novel complex perovskite. The samples were produced by the standard solid-state reaction recipe. Crystallographic analysis was performed by Rietveld refinement of experimental X-ray diffraction patterns. Results show that this material crystallizes in a perovskite with orthorhombic structure, which corresponds to the Pnma (#62) space group. From the Curie-Weiss fitting on the curve of susceptibility as a function of temperature we establish that the ordering corresponds to a paramagnetic-antiferromagnetic transition, with a Weiss temperature q=-18,5 K, which is compatible with the behavior of the inverse of susceptibility as a function of temperature, and a Néel temperatura TN=50,8 K. The Curie constant allowed for us to obtain an effective magnetic moment of 15,7 mB. The result of magnetization as a function of the applied field, measured at T=50 K, shows a magnetic hysteresis behavior that corroborate the magnetic ordering present for this temperature value. Measurements of the dielectric constant as a function of applied frequencies at room temperature give as a result a high relative dielectric constant (e=780). The reflectance curve as a function of the wavelength reveals the typical behavior of a double perovskite-like material and permits to obtain the energy gap 2,74 eV, which is characteristic of a semiconductor material.

CRYSTALLOGRAPHIC, FERROELECTRIC AND ELECTRONIC PROPERTIES OF THE Sr2ZrTiO6 DOUBLE PEROVSKITE

2013 ◽  
Vol 27 (20) ◽  
pp. 1350141 ◽  
Author(s):  
D. A. LANDÍNEZ TÉLLEZ ◽  
L. A. CARRERO BERMÚDEZ ◽  
C. E. DELUQUE TORO ◽  
R. CARDONA ◽  
J. ROA-ROJAS
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Energy Gap ◽  
Double Perovskite ◽  
Crystallographic Analysis ◽  
Partial Density ◽  
X Ray Diffraction ◽  
Saturation Polarization ◽  
The Density Functional Theory ◽  
Diffraction Patterns

In this paper, we report structural analysis, ferroelectric behavior and electronic structure of Sr 2 ZrTiO 6 double perovskite. Samples were produced by the solid state reaction recipe. Crystallographic analysis was performed by Rietveld refinement of experimental X-ray diffraction patterns. Results show that this material crystallizes in a tetragonal perovskite structure which corresponds to the space group I4/m. The curve of polarization as a function of applied voltage evidences a ferroelectric character with saturation polarization on the application of voltages up to 1800 V. Calculations of density of states and band structure for this manganite-like material were carried out by means of the density functional theory implemented into the Wien2k code. Results of total and partial density of states reveal the insulator character of this material with an energy gap of 2.66 eV.

Dielectric Properties and Photocatalytic Activity of Single Phase BFO Prepared by Chemical Coprecipitation

2012 ◽  
Vol 512-515 ◽  
pp. 1235-1239 ◽  
Author(s):  
Xiao Lin Liu ◽  
Xiao Liang Dou ◽  
Huan Ying Xie ◽  
Jian Feng Chen
Keyword(s):  
Dielectric Constant ◽  
Photocatalytic Activity ◽  
Dielectric Properties ◽  
Bismuth Ferrite ◽  
Magnetic Hysteresis ◽  
Magnetic Ordering ◽  
Rhombohedral Phase ◽  
Magnetic Hysteresis Loop ◽  
Chemical Coprecipitation ◽  
Potential Applications

Bismuth ferrite (BFO), one of very few multiferroics with simultaneous coexistence of ferroelectric and magnetic ordering, has attracted much attention due to its potential applications for new memory devices. In this work, 30~90 nm BFO powders with single rhombohedral phase were prepared by chemical coprecipitation method and after calcining of 500oC. Photocatalytic properties of the powders and dielectric properties of BFO ceramic were characterized, respectively. Cut-off wavelength of the powders at 590 nm exhibited efficient ultraviolet photocatalytic activity, which has been demonstrated by a photocatalytic result. 0.3g BFO powders can make 10 ppm RhB aqueous solution (100 ml) to decolorize and RhB decomposition rate reached to 95% during 3 hr UV irradiation. BFO ceramic can be obtained by sintering the green disc compacted with BFO powders at 800oC for 1h. Its dielectric constant is t about 250, and its dielectric loss is 0.03 at below 100 oC in the frequency range of 102 ~ 104 Hz and up to 1200 at 200 oC under 1 kHz, respectively. Reduced polarization is found due to higher loss and lower dielectric constant of the ceramic when the measuing frequency is more than 104 Hz. Magnetic hysteresis loop of BFO ceramic also shows weaker magnetic property, which may be attributed to size confinement effect of the nanostructures.

Preparation and Study the Electrical and Optical Properties for (PVA-PEG-Sr2O3) Nanocomposites

2021 ◽  
Vol 19 (10) ◽  
pp. 47-55
Author(s):  
Safa Ahmed Jabbar Al-Rubaye ◽  
Nassar A. Al-lsawi ◽  
Ali R. Abdulridha
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Energy Gap ◽  
Antimony Oxide ◽  
Optical And Electrical Properties ◽  
Electrical And Optical Properties ◽  
Constant E

In the presented work, the optical and electrical properties of composite materials (PVA-PEG-Sr2O3) were measured, as the electrical properties were verified at various frequencies in range of 100 Hz-6 MHz. In addition, the experimental results showed that the increase in frequency causes a reduction in the dielectric loss (δ) and dielectric constant (ɛ), and there is an increase in ɛ due to the increase in the content of antimony oxide (Sr2O3). It increases with increasing frequency and decreases with increasing Sr2O3 content in PVA-PEG-Sr2O3 compounds, the result of the optical properties of the nanoparticles (PVA-PEG-Sr2O3) showed that the values transmittance and energy gap were reduced with the increases in the concentrations of Sr2O3 NPs, whereas the values related to extinction coefficient, absorption coefficient, optical conductivity, refractive index, and dielectric constant (imaginary, real) were increased with increase in the concentration of Sr2O3 NPs.

Structural, magnetic and electrical properties of RFeO3 (R= Dy, Ho, Yb & Lu) compounds

2021 ◽  
Author(s):  
Mehrnoush Nakhaei ◽  
Davoud Sanavi Khoshnoud
Keyword(s):  
Dielectric Constant ◽  
Rare Earth ◽  
Electrical Properties ◽  
Sol Gel ◽  
Magnetic Hysteresis ◽  
Combustion Method ◽  
Rare Earth Ion ◽  
Gel Combustion ◽  
Diffraction Patterns ◽  
Magnetic And Electrical Properties

Abstract The nanosized rare earth orthoferrites (RFeO3) with R= Dy, Ho, Yb & Lu were synthesis by sol-gel combustion method. The effects of varying rare earth ion on structural, magnetic and electrical properties of RFeO3 nanoparticles (NPs) have been studied. X-ray diffraction patterns of the prepared samples were in single phase with orthorhombic structure with space group Pbnm. The magnetic hysteresis measurements indicated the decrease in the antiferromagnetic nature of RFeO3 from Dy to Lu that can be ascribed to increasing noncollinear Fe moments because of the structural distortion. The electric hysteresis of these samples exhibited narrow electric field-polarization loops. The frequency response of dielectric constant of RFeO3 explained based on dipole relaxation process and Maxwell-Wagner model. In addition, the temperature dependence of dielectric constant illustrated an anomaly in the vicinity of the Neel temperature of RFeO3 compounds. This occurrence indicate that a coupling exist between magnetic and electric orders.

STRUCTURAL, MAGNETIC AND ELECTRONIC PROPERTIES OF THE Sr2CoNbO6 COMPLEX PEROVSKITE

2013 ◽  
Vol 27 (28) ◽  
pp. 1350171 ◽  
Author(s):  
J. M. RENDÓN RAMÍREZ ◽  
O. A. ALMANZA M. ◽  
R. CARDONA ◽  
D. A. LANDÍNEZ TÉLLEZ ◽  
J. ROA-ROJAS
Keyword(s):  
Electronic Properties ◽  
Structure Prediction ◽  
Density Functional ◽  
Energy Gap ◽  
Magnetic Ordering ◽  
Double Perovskite ◽  
Rietveld Analysis ◽  
Lattice Parameters ◽  
Blocking Temperature ◽  
Generalized Gradient

We report a study of crystallographic parameters of the Sr 2 CoNbO 6 double perovskite obtained from Rietveld analysis of X-ray diffraction data and electronic properties predictions using the density functional theory (DFT). The Sr 2 CoNbO 6 material was prepared by the citrate precursor method. Diffraction analysis reveal that this material crystallizes in a structure which is tetragonal with lattice parameters a = 5.5960(3) Å and c = 7.9881(1) Å (space group I4/m). The density of states of Sr 2 CoNbO 6 tetragonal distorted structure was calculated using DFT within the generalized gradient approximation. Results predict the semiconductor characteristics of this material which is majority due to the 3d- Co orbital with a energy gap of 0.2 eV. Structural lattice parameters obtained from the Rietveld refinement present a matching of 97% with that obtained from the Structure Prediction Diagnostic Software and 98% with the theoretical DFT results. Measurements of magnetization as a function of temperature evidence the occurrence of a magnetic ordering transition at T = 220 K and a marked irreversibility with a blocking temperature of 250 K for applied fields up to 100 Oe, which disappears for higher fields. Electronic paramagnetic resonance experiments evidence that the valence Co 3+ is the most possible in the synthesized material.

scholarly journals Investigation of Structural, Microstructural, Dielectrical and Magnetic Properties of Bi3+ Doped Manganese Spinel Ferrite Nanoparticles for Photonic Applications

2020 ◽  
Author(s):  
V. Jagadeesha Angadi ◽  
H.R. Lakshmiprasanna ◽  
K. Manjunatha
Keyword(s):  
Dielectric Constant ◽  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Magnetic Hysteresis ◽  
Complex Impedance ◽  
Combustion Method ◽  
Solution Combustion ◽  
Dielectric Parameters ◽  
The Real ◽  
Diffraction Patterns

The structural, microstructural, and magnetic properties of Mn1-xBixFe2O4 (where x = 0.0, 0.05, 0.1, 0.15, and 0.2) nanoparticles prepared by solution combustion method were investigated. Rietveld-refined X-ray diffraction patterns confirm the single-phase formation with space group Fd3m having spinel cubic structure. The porous nature of the samples was confirmed by scanning electron microscopy (SEM). Composition values of the theoretical stoichiometry and energy-dispersive spectroscopy (EDS) composition values are well matched for all samples. The dielectric parameters such as real part of dielectric constant, imaginary part of dielectric constant, and dielectric loss tangent decrease with the increase in frequency. The AC conductivity increases with increase in the Bi3+ concentration. The real part of complex impedance decreases with the increase in frequency. Cole-Cole plots reveal that one semicircle was obtained for each of the samples. The real and imaginary parts of electric modulus vary with frequency. The magnetic hysteresis curves of all samples reveal the soft magnetic material nature. We observed S esteems began uniquely from the higher superparamagnetic, we would have watched the monotonic decrease in S with increase in Bi3+ concentration. Furthermore, the magnetic parameters were estimated.

Morphology of Σ3{/70.53°} grain boundaries in a C15 intermetallic compound

1994 ◽  
Vol 52 ◽  
pp. 684-685
Author(s):  
Fuming Chu ◽  
D. P. Pope ◽  
D. S. Zhou ◽  
T. E. Mitchell
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Crystallographic Analysis ◽  
Laves Phase ◽  
Second Phase ◽  
Bright Field Image ◽  
Boundary Edge ◽  
Arc Melting ◽  
Fcc Lattice ◽  
Diffraction Patterns

A C15 Laves phase, HfV2+Nb, shows promising mechanical properties and here we describe the structure of its grain boundaries. The C15 Laves phase has a fcc lattice with a=7.4Å. An alloy of composition Hf14V64Nb22 (including a C15 matrix and a second phase of V-rich bcc solution) was made by arc-melting. The alloy was homogenized at 1200°C for 120h. Preliminary study concentrated on Σ3{<110>/70.53°} grain boundaries in the C15 phase using Philips 400T and CM 30 microscopes.The most-commonly observed morphology of Σ3{<110>/70.53°} grain boundaries in the C15 phase is a faceted boundary. A bright field image (BFI) of the faceted boundary and the corresponding diffraction patterns with the grain boundary edge-on are shown in Fig. 1(a). From the diffraction patterns using a <110> zone axis for both grains, it is obvious that this is a Σ3{<110>/70.53°} grain boundary. Crystallographic analysis shows that the Σ3{<110>/70.53°} grain boundaries selectively facet with the following relationships between the two grains: {111}1//{111}2, {112}1//{112}2, {111}1//{115}2, and {001}1//{221}2.

Effect Of Moisture On The Physical Properties Of Polyimide Films

1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Electrical Properties ◽  
Relative Humidity ◽  
Quartz Crystal ◽  
Moisture Absorption ◽  
Relative Dielectric Constant ◽  
Moisture Uptake ◽  
Polyimide Films ◽  
Effect Of Moisture

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.

The Research on the Piezoelectric and Dielectric Properties of Bi0.5(Nak)0.5-BaTiO3 Lead-Free Ceramics

2014 ◽  
Vol 1035 ◽  
pp. 422-425
Author(s):  
Jian Yong Guo ◽  
Tao Sheng Zhou ◽  
Ji Hong Liao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Perovskite Structure ◽  
Relative Dielectric Constant ◽  
Lead Free ◽  
Reactive Sintering ◽  
Lead Free Ceramics ◽  
Xrd Patterns ◽  
Sintering Method

The Bi0.5(Na1-xKx)0.5-yBaTiO3(BNK-BT) lead-free ceramics have been prepared by the solild reactive sintering method. XRD patterns show the BNK-BT ceramics had a perovskite structure. Piezoelectric and dielectric properties of the ceramics also have been studied. The results show that the samples had the best piezoelectric and dielectric properties when x=0.20, y=0.10. And the maximum of d33is 149 pC/N, while the relative dielectric constant is 1087.

The Processing and Properties of Multilayer Interconnection Structures Using Thermoset Films Derived from Bisbenzocyclobutene.

1989 ◽  
Vol 154 ◽  
Author(s):  
P. H. Townsend ◽  
D. C. Burdeaux ◽  
S. F. Hahn ◽  
M. Thomsen ◽  
J. N. Carr
Keyword(s):  
Dielectric Constant ◽  
Thermal Cycling ◽  
Relative Dielectric Constant ◽  
Electrical Characteristics ◽  
Processing Conditions ◽  
Dielectric Layers ◽  
Significant Change

AbstractMultilayer interconnection structures incorporating a novel polymeric dielectric derived from a bis-benzocyclobutene(bis-BCB) monomer have been fabricated. This paper discusses the processing conditions for the construction of these circuits and describes electrical characteristics of the dielectric layers. The relative dielectric constant of the BCB film was 2.7. Thermal cycling produced no significant change in the conductance of three level metal via chains through two layers of the polymer.

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