scholarly journals Structure and magnetic properties of Bi-doped calcium aluminosilicate glass microspheres

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Melinda Majerová ◽  
Martin Škrátek ◽  
Branislav Hruška ◽  
Andrej Dvurečenskij ◽  
Peter Švančárek ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Xrd Analysis ◽  
Aluminosilicate Glass ◽  
Ferromagnetic Behavior ◽  
Glass Microspheres ◽  
X Ray ◽  
Prepared Glass ◽  
Calcium Aluminosilicate ◽  
Weak Ferromagnetic

Abstract Bi-doped CaO–Al2O3–SiO2 glass microspheres with Ca2Al2SiO7 (gehlenite) composition were prepared by combination of solid-state reaction and flame synthesis. The concentration of Bi was 0.0, 0.5, 1 and 3 mol %. The chemical composition of prepared glass microspheres was determined by X-ray fluorescence (XRF). The structural and magnetic properties of prepared glass microspheres and their polycrystalline analogues were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman spectroscopy and SQUID magnetometry. The closer inspection of glass microspheres surface by SEM confirmed smooth surface and revealed no features indicating presence of crystalline phases. All Bi-doped microspheres are X-ray amorphous, however in case of undoped microspheres XRD detected traces of crystalline gehlenite. XRD analysis of samples crystallized at 1273 K for 10 h revealed the presence of gehlenite as the main crystalline phase. The presence of gehlenite in crystallized samples were also confirmed by Raman spectroscopy. All samples (glass microspheres and their crystalline analogues) showed diamagnetic or weak ferromagnetic behavior at room temperature, whereas paramagnetic or weak ferromagnetic behavior was observed at 2 K.

Dielectric Properties and Raman Spectroscopy in Ca-Substituted Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2011 ◽  
Vol 324 ◽  
pp. 298-301 ◽  
Author(s):  
Roy Jean Roukos ◽  
Olivier Bidault ◽  
Julien Pansiot ◽  
Ludivine Minier ◽  
Lucien Saviot
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Rhombohedral Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray

Lead free Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5TiO3)1-x(CaTiO3)x (NBT-CT) piezoelectric ceramics with the perovskite structure were studied. The NBT and NBT-CT samples were synthesized using a solid-state reaction method and characterized with X-ray diffraction (XRD), Raman spectroscopy and dielectric measurements for several compositions (x = 0, 0.07, 0.15) at room temperature. The XRD analysis showed a stabilization of a rhombohedral phase at a low concentration of Ca (0 < x <0.15), whereas Raman spectra reveal a strong modification for the sample with x = 0.15. The dielectric properties of these ceramics were studied by measuring impedance in the 79-451K temperature range for unpoled and field cooling with an electric field (FC) conditions.

scholarly journals Structure-Property Relation in Varieties of Millets Grown in Karnataka

2020 ◽  
pp. 1-9
Author(s):  
M. S. Suhas ◽  
Nagendra S. Kamath ◽  
P. Koushik ◽  
Vasudeva Singh ◽  
R. Somashekar
Keyword(s):  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Foxtail Millet ◽  
Elemental Distribution ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Property Relation ◽  
Magnetic Techniques

Aim: This study aims to establish structure-property relation of the varieties of millets grown in Karnataka. Study Design: Seven different varieties of millets were collected from the farms in Chitradurga district from the state of Karnataka in India. Place and Duration of Study: This study was conducted between January and April 2020 at the Vijnana Bhavan, University with Potential for excellence, University of Mysore, Karnataka Methodology: Magnetic property and characterization for seven out of the nine varieties of millets grown in Chitradurga, Hiriyur and Khandenahalli of Karnataka were carried out using X-ray diffraction studies (XRD), Energy Dispersive X-ray analysis (EDAX), Raman spectroscopy, SEM and Xplore AC magnetic techniques to understand the physical properties of these samples and to find out the structure-property relation in these millets. Results: The Foxtail millet is unique in terms of crystallites size, elemental distribution and magnetic properties. The structure-property relation of all the millets is determined. Conclusion: It is evident from these studies that all the millets are diamagnetic in nature, crystalline like order is less and the major component in all these millets is cellulose. Also the Foxtail millet has excellent structure-property relation.

scholarly journals Characterization of Pressure-induced Phase Transition on [Co(bpy)3](NO3)2·3H2O

2014 ◽  
Vol 70 (a1) ◽  
pp. C57-C57
Author(s):  
Ya-Wen Lee ◽  
Yu-Chun Chuang ◽  
Jyh-Fu Lee ◽  
Chi-Rung Lee ◽  
Chih-Ming Lin ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Spin Transition ◽  
Xrd Analysis ◽  
External Pressure ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

The pressure-induced phase transition study of high-spin (HS) compound, [Co(bpy)3](NO3)2·3H2O (bpy = 2,2'-bipyridine), is characterized by powder x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), Raman spectroscopy, and theoretical calculations. The results indicate that the HS ground state t2g5eg2 on Co(II) is gradually transformed to low-spin (LS) state with configuration t2g6eg1 . This phase transition behavior is similar to the thermal-induced spin crossover phenomenon once it is incorporated into certain framework. In this study, we put the compound into diamond anvil cell and applied physical pressure to replace the framework effect. To analyze the x-ray absorption near edge structure (XANES) and Raman spectroscopy, the finite difference method for near-edge structure (FDMNES) and density functional theory (DFT) calculations are applied to illustrate the experimental spectroscopies, respectively. In XANES results, an intersection point around 7756.33 eV beyond 1.73 GPa is assigned as the critical point between HS and LS state. The extended x-ray absorption fine structure (EXAFS) analysis indicates that the averaged Co-N bond lengths is 2.127(7) Å at HS state and decreased to 1.950(4) Å at LS state. Based on XRD analysis, the external pressure reduces the hexagonal cell constants from a = 13.77(3) Å and c = 21.71(3) Å to a = 13.37(5) Å and c = 21.11(1) Å. According to those experimental results, the mechanism of such pressure-induce spin transition can be interpreted as the enhancement of intermolecular interaction by increasing the external pressure.

Magnetic and Magneto-Optical Properties of Sputter-Deposited and Annealed Co-Pt Alloys

1994 ◽  
Vol 343 ◽  
Author(s):  
Sung-Eon Park ◽  
Pu-Young Jung ◽  
Ki-Bum Kim ◽  
Seh-Kwang Lee ◽  
Soon-Gwang Kim
Keyword(s):  
Magnetic Properties ◽  
Perpendicular Magnetic Anisotropy ◽  
Xrd Analysis ◽  
Atomic Scale ◽  
Alloy Films ◽  
X Ray ◽  
Transmission Electron ◽  
Ordered Phases ◽  
Pt Alloy ◽  
Sputter Deposited

ABSTRACTWe have produced Co1-xPtX (X = 0.53 and 0.75) alloy films using DC magnetron sputtering and investigated their magnetic properties using vibrating sample magnetometry(VSM) and Kerr hysteresis loop tracer. The as-deposited Co-Pt alloy films show a strong in-plane magnetization. By annealing the alloy samples, we have identified that the magnetic properties are drastically changed. While the magnetic properties of the Co0 25Pt0 75 alloy films show no noticeable changes, the coercivity and the squareness of the Co0.47Pt0.53 alloy films are drastically increased after annealing. Transmission electron microscopy(TEM) and x-ray diffractometry(XRD) analysis showed that CoPt(L10) and Co-Pt3 (L12) ordered phases, respectively, are formed in each case with a strong (11) texture. We suggest that the perpendicular magnetic anisotropy in the Co-Pt system does not depend on the mere textureness of the layer but strongly depends on the arrangement of Co and Pt at an atomic scale.

Investigation of Magnetic Properties and Nanostructure of Fe2.75Mn0.25O4@ PANI Materials and their Potential as the Magnetic Ink

2020 ◽  
Vol 855 ◽  
pp. 308-314
Author(s):  
Nadiya Miftachul Chusna ◽  
Sunaryono ◽  
Yunan Amza Muhammad ◽  
Rosabiela Irfa Andin ◽  
Ahmad Taufiq
Keyword(s):  
Magnetic Properties ◽  
Crystal Size ◽  
In Situ Polymerization ◽  
Xrd Analysis ◽  
Hysteresis Curve ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polymerization Method

The Fe2.75Mn0.25O4 nanoparticles were successfully synthesized by using the coprecipitation method, while the Fe2.75Mn0.25O4@PANI materials were successfully fabricated by using the in situ polymerization method. This research aimed to investigate the magnetic properties and nanostructure of the Fe2.75Mn0.25O4 nanoparticles and Fe2.75Mn0.25O4@PANI materials. Some characterizations of the samples were successfully carried out by using X-Ray Diffraction (XRD) instruments, Fourier Transform Infrared (FTIR), and Vibrating Sample Magnetometer (VSM) each of which was conducted to characterize the crystal structure, functional groups, morphology, and the magnetic properties of the materials. The XRD analysis results showed that the Fe2.75Mn0.25O4@PANI materials had a crystal size of 8.09 nm. Meanwhile, the FTIR spectrum represented vibrations due to the atomic bonds that made up the Fe2.75Mn0.25O4@PANI materials. Furthermore, the hysteresis curve from the VSM characterization results showed that the Fe2.75Mn0.25O4@PANI material saturation magnetization value was around 2.85 emus/g. From those characterization results, the Fe2.75Mn0.25O4@PANI materials are very potential to be applied as magnetic ink

The origin of ferromagnetism of Co-doped TiO2 nanoparticles: Experiments and theory investigation

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650296 ◽  
Author(s):  
Suyin Zhang ◽  
Zhongpo Zhou ◽  
Rui Xiong ◽  
Jing Shi ◽  
Zhihong Lu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
First Principles ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
First Principles Calculation ◽  
Ferromagnetic Behavior ◽  
X Ray ◽  
3D Electron ◽  
Co Doped

A series of Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ([Formula: see text] = 0.01, 0.03, 0.05, 0.07) nanoparticles were synthesized by sol–gel method. The X-ray diffraction, transmission electron microscopy, Raman analysis and X-ray photoelectron spectroscopy ruled out the signatures of Ti[Formula: see text], Co-clusters or any other oxides of Co. The ferromagnetic behavior was clearly observed at room temperature in doped samples with saturation magnetization [Formula: see text] of the order of 0.008–0.035 emu/g depending on doping concentrations. The saturation magnetization is found to be increased with the Co contents increasing from 1% to 7%. From the plot of the M–T curve, we obtain the [Formula: see text] as [Formula: see text][Formula: see text]515 K for 5% Co-doped TiO2. Oxygen vacancies were detected from the photoluminescence (PL) measurement. Magnetic properties analyses and PL analyses showed that oxygen vacancies probably played a major role in ferromagnetism of the Ti[Formula: see text]Co[Formula: see text]O2 system with Co substituting for Ti. The first-principles calculation was performed to investigate the magnetic properties of Co-doped TiO2 nanoparticles. It can be found that the major magnetic moment is from the 3d electron of Co. The experiment results are consistent with the first-principles calculation. The ferromagnetism derived from the spin-split of O-2p and Co-3d electron states caused by p–d orbit hybridization.

Effects of Eu and Ca Co-Substitution for the Improvement of Multiferroic Properties of BiFeO3

2016 ◽  
Vol 697 ◽  
pp. 288-292
Author(s):  
Xin Xu ◽  
Qi Fu Yao ◽  
Sheng Peng ◽  
Long Kai Fang ◽  
Wei Wei Mao ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spin Structure ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Structure Transition ◽  
X Ray ◽  
Multiferroic Properties ◽  
Co Doped

Pure BiFeO3 (BFO), Ca-doped and Eu/Ca-codoped BFO nanoparticles were prepared by using a sol–gel method. The effects of Eu/Ca-codoped on the structural, magnetic and ferroelectric properties of the samples were studied. The X-ray diffraction (XRD) analysis reveals a structure transition in the codoped samples. Co-doped samples were obtained with the best ferromagnetic properties, with the largest remaining magnetization Mr = 0.20 emμ/g. The structure transition may be the main cause for the origin of improved magnetic properties, which destroys the space modulated spin structure of BFO and releases the locked magnetic. In addition, the doping of Eu into BFO can reduce the leakage current and enhance the ferroelectric properties.

Structural and Magnetic Properties of Nickel Oxide Nanopowders

2010 ◽  
Vol 168-169 ◽  
pp. 341-344 ◽  
Author(s):  
Nina Mironova-Ulmane ◽  
A. Kuzmin ◽  
J. Grabis ◽  
I. Sildos ◽  
V.I. Voronin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Neutron Diffraction ◽  
Nickel Oxide ◽  
Room Temperature ◽  
Squid Magnetometry ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Antiferromagnetic Ordering ◽  
Structural And Magnetic Properties

Structure and magnetic properties of nickel oxide (NiO) nanopowders have been studied by X-ray/neutron diffraction, SQUID magnetometer, and micro-Raman spectroscopy. Our diffraction data indicate that at room temperature all NiO powders are antiferromagnetically ordered and have a rhombohedral (R-3m) phase. The SQUID magnetometry and Raman spectroscopy measurements support the presence of the antiferromagnetic ordering.

Hydrothermal Synthesis and Magnetic Properties of α-Fe2O3 Polyhedrons

2011 ◽  
Vol 233-235 ◽  
pp. 3014-3017
Author(s):  
Li Tian ◽  
Ke Long Huang
Keyword(s):  
Magnetic Properties ◽  
Hydrothermal Process ◽  
Average Diameter ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Starting Solution ◽  
Experimental Parameters ◽  
Topotactic Transformation

α-Fe2O3polyhedrons have been successfully synthesized via a one-pot hydrothermal process. The average diameter of the synthesized α-Fe2O3polyhedrons is about 0.8 μm. The structure and morphology of α-Fe2O3polyhedrons were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. And the possible formation mechanism is proposed that the α-Fe2O3polyhedrons are grown epitaxially from the FeOOH precursors by topotactic transformation. The experimental parameters play a crucial role in the growth of the α-Fe2O3polyhedrons. The results indicate that the phase and morphology of the products are greatly affected by the concentrations of disodium ethyleediamine tetracetate and NaOH in the starting solution. The magnetic properties of α-Fe2O3polyhedrons show weak ferromagnetic behavior with the saturation magnetization of 0.498 emu/g, remanent magnetization of 0.051 emu/g and coercivity of 372.81 Oe.

Synthesis and Characterization of MgFe2O4 /MgO Composite Films from Layered Double Hydroxides Precursors

2013 ◽  
Vol 690-693 ◽  
pp. 342-350
Author(s):  
Ying Chao Zhang ◽  
Ting Ting Chen ◽  
Lan Yang
Keyword(s):  
Magnetic Properties ◽  
Composite Films ◽  
Xrd Analysis ◽  
Particle Size Analysis ◽  
Molar Ratio ◽  
Size Analysis ◽  
X Ray ◽  
Single Source Precursor ◽  
Double Hydroxide ◽  
Double Hydroxides

MgFe2O4/MgO composite films have been successfully fabricated by a facile route using magnesium iron layered double hydroxide (MgFe-LDH) as a single-source precursor. This strategy mainly involves the formation of MgFe-LDH film by casting the slurry of MgFe-LDH precursor on the α-Al2O3substrate, followed by calcination at 900°C. The structure, morphology and magnetic properties of the resulting films were characterized by means of X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), laser particle size analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and vibrating sample magnetometer (VSM). The results show that the composite films are composed of spherical or elliptical grains with diameters of less than 150nm and their thickness range was 2~3 μm. EDX mapping analysis reveals that the composite films have uniform distribution of MgFe2O4particles in MgO matrix. Further investigation indicates that the magnetic properties of the composite films can be tailored by altering the Mg/Fe molar ratio of LDH precursors.

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