scholarly journals Magnetic and dielectric properties of Ca-substituted BiFeO3 nanoferrites by the sol-gel method

2018 ◽  
Vol 16 (1_suppl) ◽  
pp. 93-100 ◽  
Author(s):  
Jinpei Lin ◽  
Zeping Guo ◽  
Mei Li ◽  
Qing Lin ◽  
Kangling Huang ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Sol Gel ◽  
Diffraction Peak ◽  
Multiferroic Material ◽  
Superconducting Quantum Interference Device ◽  
X Ray ◽  
Calcination Temperatures ◽  
Main Diffraction Peak ◽  
Microwave Network Analysis

Background: A multiferroic material can simultaneously show two or more basic magnetic properties, including ferromagnetism, antiferromagnetism, and ferroelectricity. BiFeO3 is a multiferroic material with a rhombohedral distorted perovskite structure. Doping can reduce the volatility of Bi and greatly improve the magnetoelectric properties of BiFeO3. Methods: To investigate the influence of the doping content we used the following analytical methods: X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microwave network analysis (PNA-N5244A), and the Superconducting Quantum Interference Device (Quantum Design MPMS) test. Results: With the increase of Ca2+ concentration in the solution, the grain size of Bi1- xCa xFeO3 becomes smaller, showing the role of Ca2+ ions as the dopant for fine grains. The calcination temperatures are the major causes for the saturated magnetization. The residual magnetization ( Mr) and the coercive force ( Hc) decrease linearly with the increase of x value, and due to the effect of Ca2+ substitution at Bi3+ sites, which causes the valence change of Fe and/or the oxygen vacancies. Conclusions: The XRD result indicates that the diffraction peak emerges with the increase of Ca2+ and the main diffraction peak achieves a high angle. The best calcining temperature is 600 °C, and the morphology is very dependent on the calcining temperature.

Exploring Soft Magnetism in Amorphous Carbon Synthesized from Biomass

2020 ◽  
Vol 855 ◽  
pp. 154-159
Author(s):  
Fahmi Astuti ◽  
Vera Laviara Maghfirohtuzzoimah ◽  
Novita Sari ◽  
Deril Ristiani ◽  
Retno Asih ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Quantum Interference ◽  
Peak Position ◽  
Diffraction Peak ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Past ◽  
Reduced Graphene ◽  
Heating Treatment

Some studies of the usage of biomass to produce carbon-based compounds have been reported in the past. Here we report that palmyra sugar can be one of the sources to produce amorphous carbon (a-C) from biomass after the heating treatment at 250°C. In this paper, X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), Fourier Transform Infrared (FTIR) and Superconducting Quantum Interference Device (SQUID) measurements are reported in order to check the detailed properties of a-C from palmyra sugar. The XRD data at a diffraction peak position (2θ) of ~23o support the formation of a-C. The functional groups detected by FTIR spectra consist of C=C, C-C, C-O, C=O, C-H and O-H. The remnant magnetization (Mr), coercive field (Hc) and saturation magnetization are estimated as ~0.1 10-3 emu/g, ~50 Oe and ~9 10-3 emu/g, respectively. Soft ferromagnetism in a-C from palmyra sugar is confirmed, comparable with the magnetization result in the reduced graphene oxide (rGO) sample from coconut shell and rGO commercial material which have the same mixture hybridization. Some studies of the usage of biomass to produce carbon-based compounds have been reported in the past. Here we report that palmyra sugar can be one of the sources to produce amorphous carbon (a-C) from biomass after the heating treatment at 250°C. In this paper, X-Ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), Fourier Transform Infrared (FTIR) and Superconducting Quantum Interference Device (SQUID) measurements are reported in order to check the detailed properties of a-C from palmyra sugar. The XRD data at a diffraction peak position (2θ) of ~23o support the formation of a-C. The functional groups detected by FTIR spectra consist of C=C, C-C, C-O, C=O, C-H and O-H. The remnant magnetization (Mr), coercive field (Hc) and saturation magnetization are estimated as ~0.1 10-3 emu/g, ~50 Oe and ~9 10-3 emu/g, respectively. Soft ferromagnetism in a-C from palmyra sugar is confirmed, comparable with the magnetization result in the reduced graphene oxide (rGO) sample from coconut shell and rGO commercial material which have the same mixture hybridization.

Effect of Sputtering Pressure on the Formation of Semiconducting Mg2Si Films

2010 ◽  
Vol 663-665 ◽  
pp. 166-169
Author(s):  
Qing Quan Xiao ◽  
Quan Xie ◽  
Ke Jie Zhao ◽  
Zhi Qiang Yu
Keyword(s):  
Film Growth ◽  
Diffraction Peak ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Intensity ◽  
Main Diffraction Peak ◽  
Diffraction Peaks ◽  
Si Films ◽  
Sputtering Pressure

Semiconducting Mg2Si films were fabricated on Si (111) substrates by magnetron sputtering and subsequent annealing, and the effects of sputtering pressure on the Mg2Si film growth were studied. The structural and morphological properties of Mg2Si films were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the Mg2Si (220) main diffraction peak intensity increased and then decreased with the increasing of sputtering pressure. The (220) diffraction peak got its maximum at 3.0 Pa sputtering pressure. The intensity of Mg2Si (200) and (400) diffraction peaks increased rapidly as the sputtering pressure decreased when the pressure was lower than 1.5 Pa. The films prepared at higher sputtering pressure had very irregular microstructures, and the surface of semiconducting Mg2Si films became smoother with the decreasing of the sputtering pressure.

Structural and ferromagnetic properties of Cu-doped GaN

2007 ◽  
Vol 22 (5) ◽  
pp. 1396-1405 ◽  
Author(s):  
B. Seipel ◽  
R. Erni ◽  
Amita Gupta ◽  
C. Li ◽  
F.J. Owens ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Electron Gun ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
Calcination Process ◽  
X Ray ◽  
Lattice Constants ◽  
Gan Crystal ◽  
Electron Energy Loss ◽  
Atomic And Electronic Structure

The wurtzite polymorph of GaN was calcined with CuO in flowing nitrogen. As a result of this processing, both superconducting quantum interference device magnetometry and ferromagnetic resonance studies showed ferromagnetism in these samples at room temperature. These magnetic results are qualitatively consistent with very recent first-principle calculations [Wu et al., Appl. Phys. Lett.89, 062505 (2006)] that predict ferromagnetism in Cu-doped GaN. We focus in this paper on analyzing changes in the GaN atomic and electronic structure due to calcination with CuO using multiple analytical methods. Quantitative powder x-ray diffraction (XRD) showed changes in the lattice constants of the GaN due to the incorporation of copper (and possibly oxygen). Energy-dispersive x-ray spectroscopy proved the incorporation of copper into the GaN crystal structure. Electron-gun monochromated electron energy loss spectroscopy showed CuO calcinations-induced GaN band gap changes and indicated changes in the atomic arrangements due to the calcination process. The fine structure of the N K-edge showed differences in the peak ratios with respect to higher nominal CuO contents, corresponding to an increase in the c-lattice constant as confirmed by XRD.

Synthesis and crystal chemistry of the new compounds GdBa4Cu3O8.5+δ and DyBa4Cu3O8.5+δ

1999 ◽  
Vol 14 (2) ◽  
pp. 334-339 ◽  
Author(s):  
Y. T. Zhu ◽  
E. J. Peterson ◽  
P. S. Baldonado ◽  
J. Y. Coulter ◽  
D. E. Peterson ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Lattice Parameter ◽  
Inversion Symmetry ◽  
Iodometric Titration ◽  
Powder Diffraction Data ◽  
Superconducting Quantum Interference Device ◽  
Space Group ◽  
X Ray ◽  
Space Groups ◽  
New Compounds

Two new compounds, GdBa4Cu3O8.5+δ (Gd143) and DyBa4Cu3O8.5+δ (Dy143), were synthesized from precursors Gd2O3, Dy2O3, BaO2, and CuO at 1000 °C in an oxygen atmosphere. The oxygen stoichiometric value δ was found to be 0.68 for Gd143 and 0.6 for Dy143 by iodometric titration. Rietveld refinement of x-ray powder diffraction data showed that Gd143 belongs to the space group Pm3 while Dy143 belongs to the space group P23. The two space groups, Pm3 and P23, are very similar. Their main difference is that P23 does not have the inversion symmetry of Pm3. Both compounds have a cubic unit cell with a lattice parameter of 8.16528 ± 0.00006 Å for Gd143 and 8.10807 ± 0.00010 Å for Dy143. Superconducting quantum interference device (SQUID) measurement indicated that neither compound was superconductive down to 5 K.

Hydrothermal Synthesis and Room Temperature Ferromagnetism of Ni-Doped Rod-Like ZnO Particles

2014 ◽  
Vol 934 ◽  
pp. 71-74
Author(s):  
Lian Mao Hang ◽  
Zhao Ji Zhang ◽  
Zhi Yong Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Hexagonal Wurtzite Structure ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Particles

Ni-doped rod-like ZnO particles with doping concentration of 1 at.% were synthesized at 200°C by hydrothermal method and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and superconducting quantum interference device (SQUID). The results show that the as-synthesized samples are pure hexagonal wurtzite structure without metallic Ni or other secondary phases and display rod-like shape with smooth surface. The magnetization measurements reveal that the Ni-doped rod-like ZnO particles show ferromagnetic behavior at room temperature. The saturation magnetization and coercive field are 0.0046 emu/g and 15 Oe, respectively.

Investigation of ZnO/CuO/Nanographene Platelets Composites Catalyst for the Degradation of Methylene Blue from Aqueous Solution

2016 ◽  
Vol 864 ◽  
pp. 117-122 ◽  
Author(s):  
Hesni Shabrany ◽  
Hendry Tju ◽  
Ardiansyah Taufik ◽  
Rosari Saleh
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Catalytic Activity ◽  
Visible Light ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Ultrasound Irradiation ◽  
X Ray Diffraction ◽  
X Ray

This paper discusses the catalytic activity of ZnO/CuO/nanographene platelets composites under visible light and ultrasound irradiation separately. The ZnO/CuO/nanographene platelets composites were synthesized using a sol-gel method. X-ray diffraction and nitrogen adsorption spectroscopy were employed to investigate the structural and surface area of the catalyst. The catalytic activity results showed that the presence of nanographene platelets in ZnO/CuO nanocomposites improved its efficiency in degrading methylene blue. A scavenger method was also used to understand the role of charged carriers and the active radical involved in the catalytic activity.

scholarly journals The role of the ionic liquid C6C1ImTFSI in the sol–gel synthesis of silica studied using in situ SAXS and Raman spectroscopy

2015 ◽  
Vol 17 (15) ◽  
pp. 9841-9848 ◽  
Author(s):  
Moheb Nayeri ◽  
Kim Nygård ◽  
Maths Karlsson ◽  
Manuel Maréchal ◽  
Manfred Burghammer ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ionic Liquid ◽  
Sol Gel ◽  
Chemical Changes ◽  
X Ray ◽  
X Ray Scattering ◽  
Sol Gel Synthesis ◽  
Ray Scattering

Structural and chemical changes during the sol–gel synthesis of silica using an ionic liquid are investigatedin situand simultaneously by X-ray scattering and μ-Raman spectroscopy.

Preparation of LaFeO3 particles by sol-gel technology

1998 ◽  
Vol 13 (2) ◽  
pp. 451-456 ◽  
Author(s):  
C. Vázquez-Vázquez ◽  
P. Kögerler ◽  
M. A. López-Quintela ◽  
R. D. Sánchez ◽  
J. Rivas
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Infrared Spectroscopy ◽  
Sol Gel ◽  
Diffraction Peak ◽  
Gel Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferromagnetic Component ◽  
Peak Broadening

The study of submicroscopic particles in already known systems has resulted in a renewed interest due to the large differences found in their properties when the particle size is reduced, and because of possible new technological applications. In this work we report the preparation of LaFeO3 particles by the sol-gel route, starting from a solution of the corresponding metallic nitrates and using urea as gelificant agent. Gels were decomposed at 200 °C and calcined 3 h at several temperatures, T, in the range 250–1000 °C. The samples were structurally characterized by x-ray diffraction (XRD) showing that the orthoferrite crystallizes at T as low as 315 °C. From the x-ray diffraction peak broadening, the particle size was determined. The size increases from 60 to 300 nm as the calcination T increases. Infrared spectroscopy was used to characterize gels and calcined samples. From these studies a mechanism for the gel formation is proposed. Study of the magnetic properties of LaFeO3 particles shows the presence of a ferromagnetic component which diminishes as the calcination temperature increases, vanishing at T = 1000 °C.

Mass Absorption Corrected X-Ray Powder Diffractograms. Part 1: Measuring Pyrite in Powdered Coals

1990 ◽  
Vol 5 (1) ◽  
pp. 44-47 ◽  
Author(s):  
David L. Wertz
Keyword(s):  
Absorption Coefficient ◽  
Limit Of Detection ◽  
Diffraction Peak ◽  
Mass Absorption Coefficient ◽  
Measured Intensity ◽  
X Ray ◽  
Mass Absorption ◽  
Powdered Coal ◽  
Analysis Protocol

AbstractAn X-ray analysis method has been developed for the quantitative analysis of pyrite (FeS2) in coals and lignites. Requiring neither the use of external or internal references, the method linearly relates diffraction peak area in the absorption corrected X-ray diffractogram obtained from the finely powdered coal to the pyrite abundance. The [311] diffraction peak of pyrite (FeS2) has been used to develop the analysis protocol. The Argonne premium coals have been used as the experimental subjects. The abundance of pyrite in each coal has been measured from the absorption corrected diffractograms, which has been constructed from the experimentally measured diffraction intensities and the mass absorption coefficient of each coal sample. The accuracy (accessed from the figure-of-merit and the net count uncertainty associated with the 1.63 Å pyrite peak) as well as the lower limit of detection for pyrite in these coals is presented. The role of the mass absorption coefficient in the conversion of the measured intensity to the absorption corrected intensity is discussed.

scholarly journals SYNTHESIS OF CERIUM YTTRIUM COSTABILIZED ZIRCONIUM DI-OXIDE BY SOLGEL PROCESS

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Kavitha Rani N ◽  
Dr. M C Jagath ◽  
Dr. K. N. Anuradha ◽  
Dr. Rajeshwari P ◽  
Dr Mahesh G. Emmi
Keyword(s):  
Tetragonal Phase ◽  
Zirconium Dioxide ◽  
Sol Gel ◽  
Compositional Analysis ◽  
X Ray ◽  
Multiphase Materials ◽  
Calcination Temperatures ◽  
Barrier Coating ◽  
Pure Zirconia ◽  
Sol Gel Process

The Sol–gel route was used to synthesize Ceria– Yttria co-stabilized Zirconia (CYSZ) nanoparticles. The addition of stabilizing oxides to pure Zirconia, such as CaO, MgO, CeO2, and Y2O3, allows for the formation of multiphase materials, which are referred to as CoStabilized Zirconia. Cerium Oxide CeO2 and Yttrium Oxide Y2O3 are co-stabilized with Zirconium Oxide in this study. The creation of nanostructured coatings has been shown to boost the efficiency of TBCs by lowering thermal conductivity, increasing bonding power, and increasing thermal cycling lifetime, according to researchers. The crystallinity and stabilization of cubic crystalline phases were studied by energy dispersive X-ray spectroscopy (EDAX) at different calcination temperatures in the range of 500°C to 1200°C, and surface morphology and compositional analysis were studied by scanning electron microscopy using the sol-gel process (SEM). The research yielded interesting results, but it was discovered that when Zirconium Dioxide was synthesized using the sol-gel process, the tetragonal phase was not present; thus, other methods to obtain the tetragonal phase would be needed in the future for the application of Thermal Barrier Coating.

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