Ferroelectric and magnetic characteristics of Sm-modified BiFeO3 multiferroics

2014 ◽  
Vol 92 (5) ◽  
pp. 440-447 ◽  
Author(s):  
Samita Pattanayak ◽  
R.N.P. Choudhary ◽  
Piyush R. Das
Keyword(s):  
Temperature Dependence ◽  
Solid State Reaction Method ◽  
Magnetic Characteristics ◽  
Scanning Electron Micrographs ◽  
Arrhenius Behavior ◽  
X Ray ◽  
Magnetic Parameters ◽  
Rhombohedral Crystal Structure ◽  
Universal Power Law ◽  
Rhombohedral Crystal

Samarium-modified BiFeO3 (i.e., Bi1–xSmxFeO3 (BSFO); x = 0, 0.1, and 0.2) ceramics were synthesized using a solid-state reaction method. Preliminary X-ray structural analysis shows that BSFO polycrystalline compounds have rhombohedral crystal structure. These samples showed dispersion in permittivity (εr) and dielectric loss (tanδ) at lower frequencies. The scanning electron micrographs of the compounds showed (i) the uniform distribution of grains on the samples’ surface with high density and (ii) reduction of grain size on Sm-substitution at the Bi site of BiFeO3. The materials exhibit temperature dependence of dielectric relaxation phenomena. Study of temperature dependence of dc conductivity of the materials follows Arrhenius behavior. The ac conductivity of BSFO obeys Jonscher’s universal power law. Studies of impedance and its related parameters of the materials exhibit a strong correlation between its microstructure (i.e., bulk, grain boundary, etc.), electrical and magnetic parameters.

Ferromagnetism and Luminescence of Diluted Magnetic Semiconductors GaGdN and AlGdN

2008 ◽  
Vol 1111 ◽  
Author(s):  
Shuichi Emura ◽  
Masahiro Takahashi ◽  
Hiroyuki Tambo ◽  
Akira Suzuki ◽  
Tetsuya Nakamura ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Magnetic Circular Dichroism ◽  
Peak Position ◽  
Magnetic Characteristics ◽  
Sharp Line ◽  
X Ray ◽  
Diluted Magnetic ◽  
X Ray Absorption

AbstractThe magnetic characteristics of the dilute magnetic system GaGdN are investigated by mainly soft-X-ray magnetic circular dichroism (MCD) in energy range of 1160 – 1240 eV. The strong MCD signals up to 30 % at 15K are observed. The temperature dependence of its intensity is not on simple Curie-Weiss curve and depicts three-step curve. A step around 40 – 100K suggests a new magnetic phase. The luminescence spectrum of GaGdN at low temperature is divided into three parts consisting of two broad bands around 432 nm and 503 nm and a sharp peak at 652 nm. This sharp line is assigned to the intra-transition of f – f orbital owing to the weak temperature dependence of the intensity and peak position. AlGdN grown by molecular beam epitaxy produces luminescence at 318.5 nm. X-ray absorption fine structure is examined to survey the occupancy of the Gd ion in the grown specimens.

Microwave-Assisted Solution Combustion Synthesis and Characterization of Thermoelectric Ca3Co2O6 Powders

2013 ◽  
Vol 802 ◽  
pp. 84-88
Author(s):  
Sagulthai Kahatta ◽  
Nopsiri Chaiyo ◽  
Chesta Ruttanapun ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Solution Combustion Synthesis ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Microwave Assisted ◽  
Product Characterization ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal

The microwave-assisted solution combustion synthesis was applied to the initial synthesizing of Ca3Co2O6powder using glycine as a fuel and nitrate as an oxidant. The as-synthesized powders were calcined at 700-1,000ºC for 4h. Product characterization was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The fuel-to-oxidizer molar ratio was found to affect the combustion reaction and character of the powder obtained. The phase composition of powder after calcination at various temperatures has shown that the formation of Ca3Co2O6occurs directly. The calcined powder possesses a rhombohedral crystal structure with an X-ray diffraction pattern that could be matched with the Ca3Co2O6JCPDS: 89-0629. This method is a simple way of synthesizing fine Ca3Co2O6powder with a low calcination temperature.

Temperature Dependence on Dielectric Response of La0.7Ba0.3Mn0.4Ti0.6O3 Ceramic

2015 ◽  
Vol 1107 ◽  
pp. 45-52
Author(s):  
Aaliyawani Ezzerin Sinin ◽  
Walter Charles Primus ◽  
Abdul Halim Shaari ◽  
Zainal Abidin Talib ◽  
Sinin Hamdan
Keyword(s):  
Dielectric Properties ◽  
Temperature Dependence ◽  
Low Frequency ◽  
Sintered Sample ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Low Frequencies ◽  
X Ray ◽  
Lcr Meter

Ceramic sample of La0.70Ba0.30Mn0.40Ti0.60O3 oxide has been prepared by the conventional solid-state reaction method. The sintered sample was characterized by using x-ray diffraction (XRD) and low frequency LCR meter. XRD result shows that the sample has a cubic structure with the existence of impurity phase. The dielectric properties of La0.70Ba0.30Mn0.40Ti0.60O3 measured from room temperature to 200°C shows that the dielectric permittivity is temperature dependence with strong dispersion at low frequencies. A circuit model based on the universal capacitor response function is also being used to represent the dielectric properties of the sample.

scholarly journals Development of Dielectric Film Based on Cellulose Loaded Nano-Silver and Carbon for Potential Energy Storage

2021 ◽  
Author(s):  
Sawsan Dacrory ◽  
Samir Kamel ◽  
G. M. Turky
Keyword(s):  
Temperature Dependence ◽  
Flexible Electronics ◽  
Low Cost ◽  
Broad Band ◽  
Periodate Oxidation ◽  
Interfacial Polarization ◽  
Single Step ◽  
Arrhenius Behavior ◽  
X Ray ◽  
Nano Silver

Abstract Cellulose has attracted much attention as a potential substrate for low-cost, flexible electronics. Here, new cellulose-based films embedded with nano-silver (AgNs) and carbon (C) were successfully prepared. First, cellulose was oxidized to tricarboxy cellulose (TCC) using 2,2,6,6 tetramethylpiperidine-1-oxyl followed by periodate oxidation. Then, nano-silver was prepared by polyol method and carbon was prepared via a single-step from bagasse. The structure, thermal, morphology, mechanical properties, and broad-band were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy with energy-dispersive X-ray, X-ray diffraction, and stress-strain relation. The results showed that the tensile strength and thermal stability of the films were improved. The temperature dependence of permittivity,  of the TCC film, increased in two trends. However, TCC film shows non-conducting features, especially at lower temperatures; its nanocomposites films show a semiconducting behavior, and its ac-conductivity follows the empirical Jonscher law. Although the temperature dependence of dc-conductivity of the TCC/C, shows an Arrhenius behavior with low activation energy (≈ 3.74 kJ/mol.), its investigated nanocomposites follow the well-known Vogel Fulcher Tamman equation according to the fragility of the prepared samples and/or the correlation between the interfacial polarization and conductivity.

scholarly journals Effect of V2O5 B-site substitution on the microstructure, Raman spectrum, and dielectric properties of SrBi2Ta2O9 ceramics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chia-Ching Wu ◽  
Cheng-Fu Yang
Keyword(s):  
Raman Spectrum ◽  
Dielectric Properties ◽  
Solid State Reaction Method ◽  
Layered Perovskite ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Strontium Bismuth Tantalate ◽  
Reaction Method ◽  
X Ray ◽  
Ferroelectric Characteristic

Abstract Strontium bismuth tantalate vanadate [SrBi2(Ta2−xVx)O9, SBTV] ceramics, which are bismuth-layered perovskite ferroelectrics, were synthesized through the solid-state reaction method. The effects of different sintering temperatures and V2O5 contents on the structure of the microstructure, Raman spectrum, and dielectric properties of the SBTV ceramics were investigated. As sintered at high temperature (980–1040 °C) and different V2O5 contents (x = 0.1 − x = 0.4), only disk-like grains of the SBTV ceramics were observed in the scanning electron micrographs. Preferential orientation of the crystals of the SBTV ceramics was confirmed through X-ray diffraction studies. The higher dielectric constant and Curie temperature of the SBTV ceramics compared with those of strontium bismuth tantalite (SrBi2Ta2O9, SBT) ceramics are ascribe to the partial replace of Ta5+ ions by V5+ ions in the B sites. The Curie–Weiss law and the modified Curie–Weiss law were used to discuss the normal-type or relaxor-type ferroelectric characteristic of the SBTV ceramics. The Ta5+ ion replaced by V5+ ion site in SBT ceramics to form SBTV ceramics exerted a pronounced effect on the BO6 mode, as demonstrated by Raman spectrum results.

scholarly journals Structural and magnetic properties of gadolinium modified BiFeO3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
L.M. Ramírez Guzmán ◽  
A.F. Cruz Pacheco ◽  
J.A. Gómez Cuaspud ◽  
C.A. Parra Vargas
Keyword(s):  
Photoelectron Spectroscopy ◽  
Morphological Analysis ◽  
Solid State Reaction Method ◽  
Magnetic Characteristics ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Group A ◽  
Interconnected Structure

Abstract This paper reports the synthesis and characterization of the Bi0:94Gd0:06FeO3 sample obtained by solid state reaction method. The structural and morphological analysis was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Rietveld refinement analysis, confirming the obtaining of a rhombohedral crystalline phase and R3c space group (a = b = 5.577 Å and c = 13.847 Å), with an interconnected structure. Studies by X-ray photoelectron spectroscopy (XPS) revealed trivalent oxidation states of Bi, Fe and Gd ions. The synthesized sample exhibited a non-linear M–H loop indicating a weak ferromagnetic behavior with a remnant magnetization of 6.34 emu˙mol−1 and a coercive field of 295 Oe. The obtained structural and magnetic characteristics make these materials of great interest as multiferroic components.

Synthesis of Ternary Semiconductor Silver Bismuth Telluride by Chemical Bath Deposition

2017 ◽  
Vol 751 ◽  
pp. 489-493 ◽  
Author(s):  
Patamaporn Termsaithong ◽  
Aphichart Rodchanarowan
Keyword(s):  
Chemical Bath Deposition ◽  
Bismuth Telluride ◽  
X Ray Diffraction ◽  
Solar Cell Application ◽  
X Ray ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal ◽  
Ternary Semiconductor ◽  
Cbd Method ◽  
Scanning Electron

In this study, the synthesis of the ternary semiconductor sensitized silver bismuth telluride (AgBiTe2: SBT) particles was produced in the solution of AgNO3, Bi (NO3)3×5H2O and Na2O3Te by using a chemical bath deposition (CBD) method and annealing at 200°C for 1 h. According to scanning electron microscopy (SEM), the particle size of SBT after annealing was bigger than before annealing. Based on X-ray diffraction, the SBT after annealing for 1h became more crystalline. In addition, the XRF data also demonstrated that the SBT powder consists of Ag, Bi, and Te as dominant elements. The XRD result confirms a successful growth of the SBT particles with rhombohedral crystal structure. Based on the obtaining results, the SBT particles were successfully synthesized and potentially applied for solar cell application.

Synthesis of Polycrystalline LaYO3 with Different Sintering Temperature

2015 ◽  
Vol 819 ◽  
pp. 117-122 ◽  
Author(s):  
N.A. Shafiqa ◽  
M.S. Idris ◽  
C.A. Salmie Suhana ◽  
R.A.M. Osman ◽  
T.Q. Tan
Keyword(s):  
Single Phase ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Pure Phase ◽  
Perovskite Ceramic

Synthesis of LaYO3 was carried out via conventional solid state reaction method. The polycrystalline samples were sintered at temperatures in the range of 1300 °C to 1500 °C with each deviation is 50 °C. X-ray diffraction (XRD) analysis indicated that the perovskite ceramic obtained its single phase at 1500 °C with ordered monoclinic perovskite structure. The pure phase sample showed 98.79 % relative density and scanning electron micrographs also proved that the porosity of the sample reduced when sample undergo sintering.

X-ray diffraction and microstructural studies in 2 : 17 type Sm–Co magnetic alloys containing Fe, Cu, and Zr

1999 ◽  
Vol 14 (6) ◽  
pp. 2430-2435 ◽  
Author(s):  
R. Gopalan ◽  
T. S. R. K. Sastry ◽  
A. K. Singh ◽  
V. Chandrasekaran
Keyword(s):  
Single Phase ◽  
Solution Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Rhombohedral Crystal Structure ◽  
Cast Alloys ◽  
Rhombohedral Crystal ◽  
Co Alloys ◽  
Microstructural Studies

X-ray diffraction and microstructural studies were carried out on 2 : 17 type Sm–Co alloys containing Fe, Cu, and Zr (13–14 at.% Sm, 57–60 at.% Co, 20–22 at.% Fe, 4 at.% Cu, and 3 at.% Zr) in as-cast and heat-treated conditions. Microstructural studies revealed that the as-cast alloys contain three phases. It was observed that the samples subjected to sintering at 1463 K for 45 min followed by a solution treatment at 1448 K for 1 h resulted in nearly a single-phase, rhombohedral crystal structure (Th2Zn17-type). Subsequent isothermal aging at 1123 K and ramp-cooling to 673 K resulted in a mixture of Sm2Co17- and SmCo5-type phases with the former as major phase. It was also found that samples (Sm > 13 at.%) sintered at temperatures >1463 K showed incipient melting and multiphase formation.

An XRD Phase Analysis of Al-F Re-Deposition Produced from Reactive Ion Etching

2015 ◽  
Vol 659 ◽  
pp. 575-579
Author(s):  
Chu Pong Pakpum
Keyword(s):  
Plasma Etching ◽  
Alpha Phase ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rhombohedral Crystal Structure ◽  
Xrd Phase Analysis ◽  
Rhombohedral Crystal ◽  
Composition Structure ◽  
Scanning Electron

This paper reports the analysis of the composition, structure and phase of the re-deposition material that was generated from the reaction from CF4 plasma etching on the Al2O3-TiC substrate. The re-deposition was sputtered from the etching area and deposited on a silicon coupon for analysis. The morphology of the re-deposition was investigated by scanning electron microscope (SEM) and the composite element of the re-deposition was detected by using energy dispersive x-ray spectroscopy (SEM-EDX). X-ray diffraction (XRD) was used to analyse the structure and phase of the re-deposition. The results show that the prepared re-deposition was composed of F and Al atoms, with 51.24 At% and 27.67 At%, respectively. XRD revealed that this was owing to the chemical formula AlF3, which has a rhombohedral crystal structure in the most stable alpha phase (α-AlF3).

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