scholarly journals Phase Pure Synthesis and Morphology Dependent Magnetization in Mn Doped ZnO Nanostructures

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Murtaza Saleem ◽  
Shahid Atiq ◽  
Shahid M. Ramay ◽  
Asif Mahmood ◽  
Saadat A. Siddiqi ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Electron Microscopic ◽  
Structural Morphology ◽  
X Ray ◽  
Phase Pure ◽  
Doped Zno ◽  
Mn Doped

Zn0.95Mn0.05O nanostructures were synthesized using sol gel derived autocombustion technique. As-burnt samples were thermally annealed at different temperatures (400, 600, and 800°C) for 8 hours to investigate their effect on structural morphology and magnetic behavior. X-ray diffraction and scanning electron microscopic studies demonstrated the improvement in crystallinity of phase pure wurtzite structure of Mn doped ZnO with variation of annealing temperature. Energy dispersive X-ray elemental compositional analysis confirmed the exact nominal compositions of the reactants. Electrical resistivity measurements were performed with variation in temperature, which depicted the semiconducting nature similar to parent ZnO after 5 at% Mn doping. Magnetic measurements by superconducting quantum interference device detected an enhanced trend of ferromagnetic interactions in thermally annealed compositions attributed to the improved structural morphology and crystalline refinement process.

Room Temperature Magnetic Behavior of Sol-Gel Synthesized Mn Doped ZnO

2010 ◽  
Vol 23 (4) ◽  
pp. 469-472 ◽  
Author(s):  
Murtaza Saleem ◽  
Saadat A. Siddiqi ◽  
Shahid Atiq ◽  
M. Sabieh Anwar ◽  
Saira Riaz
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Doped Zno ◽  
Mn Doped

scholarly journals CVD PREPARED Mn-DOPED ZnO NANOWIRES

2017 ◽  
Vol 24 (1&2) ◽  
pp. 125-130
Author(s):  
T.L. Phan ◽  
R. Vincent ◽  
D. Cherns ◽  
N.X. Nghia
Keyword(s):  
Magnetic Measurements ◽  
Chemical Vapor ◽  
Hexagonal Structure ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wavenumber Range ◽  
Doped Zno ◽  
Diffraction Patterns ◽  
Mn Doped

Mn-doped ZnO nanowires prepared by chemical vapor deposition (CVD) were obtained in the temperature range of 450–500°C. X-ray diffraction patterns, SEM and TEM images indicate that crystals with a hexagonal structure grow along the c axis. At low Mn-doped concentrations, photoluminescence (PL) and Raman scattering (RS) spectra are almost independent of the Mn doping. However, the increase in concentration of Mn above 1.6 at% weakens significantly the PL signal and the RS-lines intensity in the low wavenumber range of 300–480 cm-1, and concurrently increases the RS-lines intensity in the higher wavenumber range of 480-700 cm-1.. Magnetic measurements determined the Curie temperature of Mn-doped ZnO nanowire to be about 37 K.

Temperature Effects on Fluorescence Intensity of Mn-Doped ZnO Quantum Dots Derived from a Sol–Gel Method

2015 ◽  
Vol 15 (10) ◽  
pp. 8023-8027
Author(s):  
Younghoon Kwon ◽  
Jongsung Kim
Keyword(s):  
Quantum Dots ◽  
Sol Gel ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Technique ◽  
Doped Zno ◽  
Zno Qds ◽  
Mn Doped

Recently, various quantum dots (QDs) have been prepared and studied extensively due to their unique electrical and optical properties. Among them, ZnO has attracted much attention because it contains no heavy metals, is biocompatible, and can be easily prepared. In addition, doping QDs with transition metals such as Mn allows for their photo-physical properties to be modified. In this study, Mn-doped ZnO QDs were synthesized by a sol–gel technique, after which the effect of temperature on their fluorescence properties was investigated. The prepared QDs were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. In addition, their photoluminescence (PL) intensities decreased linearly with temperature between 30 and 70 °C. Intensity also decreased as the amount of Mn increased. Finally, the slope of the PL temperature dependence decreased as the amount of Mn present increased.

Magnetic Properties of Bulk Zn0.95-XMnXFe0.05O2 Prepared by Sol-Gel Method and Subsequent Hot Pressing

2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He
Keyword(s):  
Magnetic Properties ◽  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Sol Gel ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.

scholarly journals Improving Electrochemical Activity in a Semi-V-I Redox Flow Battery by Using a C–TiO2–Pd Composite Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Tsung-Sheng Chen ◽  
Shu-Ling Huang ◽  
Mei-Ling Chen ◽  
Tz-Jiun Tsai ◽  
Yung-Sheng Lin
Keyword(s):  
Energy Storage ◽  
Sol Gel ◽  
Vanadium Redox Flow Battery ◽  
Operating Voltage ◽  
Composite Electrodes ◽  
Redox Flow Battery ◽  
Flow Battery ◽  
Structural Morphology ◽  
X Ray ◽  
Combination Methods

This study developed composite electrodes used in a semi-vanadium/iodine redox flow battery (semi-V-I RFB) system and designed semi-V-I RFB stacks to provide performance comparable to that of an all-vanadium redox flow battery (all-VRFB) system. These electrodes were modified using the electroless plating method and sol-gel process. The basic characteristics of the composited electrodes, such as the surface structural morphology, metal crystal phases, and electrochemical properties, were verified through cyclic voltammetry, field emission-scanning electron microscopy, energy-dispersive X-ray spectrometry, and X-ray diffraction. The results show that the sintering C–TiO2–Pd electrode improved the electrocatalytic activity of the semi-V-I RFB system, thereby effectively increasing the energy storage ability of the system. The C–TiO2–Pd electrode was used as a negative electrode in a single semi-V-I RFB and exhibited excellent cyclic performance in a charge-discharge test of 50 cycles. The average values for coulomb efficiency, voltage efficiency, and energy efficiency were approximately 96.56%, 84.12%, and 81.23%, respectively. Moreover, the semi-V-I RFB stacks were designed using series or parallel combination methods that can effectively provide the desired operating voltage and linearly increase the power capacity. The amount of vanadium salt required to fabricate the semi-V-I RFB system can be reduced by combining large stack modules of the system. Therefore, this system not only reduced costs but also exhibited potential for applications in energy storage systems.

scholarly journals Synthesis and Characterization of Nanocrystalline ZnO Doped with Al3+ and Ni2+ by a Sol–Gel Method Coupled with Ultrasound Irradiation

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 406 ◽  
Author(s):  
M. Robles-Águila ◽  
J. Luna-López ◽  
Álvaro Hernández de la Luz ◽  
J. Martínez-Juárez ◽  
M. Rabanal
Keyword(s):  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Ultrasound Irradiation ◽  
Morphological Properties ◽  
Nanocrystalline Powders ◽  
Metallic Ions ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Zinc oxide is one of the most important semiconducting metal oxides and one of the most promising n-type materials, but its practical use is limited because of both its high thermal conductivity and its low electrical conductivity. Numerous studies have shown that doping with metals in ZnO structures leads to the modification of the band gap energy. In this work, Al-doped ZnO, Ni-doped ZnO, and undoped ZnO nanocrystalline powders were prepared by a sol–gel method coupled with ultrasound irradiation, and the results show the influence of Al3+ and Ni2+ ions in the ZnO network. The doping concentrations in ZnO of 0.99 atom % for ZnO–Al and 0.80 atom % for ZnO–Ni were obtained by X-ray Fluorescence (XRF). X-ray Diffraction (XRD) and Raman Spectroscopy showed a decreased intensity and broadening of main peaks, indicating metallic ions. The crystallite size of the sample was decreased from 24.5 nm (ZnO) to 22.0 nm (ZnO–Al) and 21 nm (ZnO–Ni). The textural and morphological properties were analyzed via Nitrogen Adsorption (BET method) and Field Emission Scanning Electron Microscopy (FESEM).

High Curie temperature perovskite BiInO3–PbTiO3 ceramics

2004 ◽  
Vol 19 (7) ◽  
pp. 2185-2193 ◽  
Author(s):  
Runrun Duan ◽  
Robert F. Speyer ◽  
Edward Alberta ◽  
Thomas R. Shrout
Keyword(s):  
Curie Temperature ◽  
Sol Gel ◽  
High Curie Temperature ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
X Ray ◽  
Oxide Powders ◽  
Phase Pure ◽  
Pbtio3 Ceramics

The extent of BiInO3 substitution in the perovskite system xBiInO3–(1 - x)PbTiO3 and the corresponding raise in the Curie temperature were investigated using thermal analysis, dielectric measurements, x-ray diffraction, and electron microscopy. Maximum tetragonal perovskite distortion (c/a = 1.082) was obtained for x = 0.20, with a corresponding Curie temperature of 582 °C. Phase-pure tetragonal perovskite was obtained for x ⩽ 0.25. Compound formation after calcining mixed oxide powders resulted in agglomerated cube-shaped tetragonal perovskite particles, which could be fired to 94.7% of theoretical density (TD). Sol-gel fabrication resulted in nano-sized tetragonal or pseudo-cubic perovskite particles, which after two-step firing, resulted in a tetragonal perovskite microstructure at as high as (x = 0.20) 98.1% of TD.

scholarly journals SYNTHESIS OF ZnO-Аg NANOPARTICLES BY SOL-GEL METHOD

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Savka Janković ◽  
Dragana Milisavić ◽  
Tanja Okolić ◽  
Dijana Jelić
Keyword(s):  
Zno Nanoparticles ◽  
Wide Spectrum ◽  
Sol Gel ◽  
Synthesis Method ◽  
Material Surface ◽  
Characterization Methods ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Zinc oxide is a highly applicable semiconductor material. Wide applica-tion of this nanomaterial is connected to wide spectrum of energy band gap, high bond en-ergy, great thermal conductivity, but also with its non-toxicity, antibacterial activity, bio-compatibility and biodegradability characteristics. The aim of this paper is synthesis and characterization of silver doped ZnO nanoparticles (ZnO:Ag NP) using sol-gel method. Ob-tained samples of silver doped ZnO nanoparticles were characterized by following tech-niques: Fourier-transform infrared spectroscopy (FTIR), UV/VIS spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spec-troscopy (EDX). Efficiency of provided synthesis method was examined by FTIR spectros-copy. XRD determined the purity and crystallinity, and wurtzite structure of synthesized material. Surface morphology and the effect of doping were examined using SEM and EDX characterization methods. Results showed better conductivity after doping ZnO nanoparti-cles with silver. SEM micrographs showed ZnO:Ag NP in the form of nanorods with a par-ticle average size of 6 nm.

Fabrication, characterization and magnetic properties of Na-doped ZnO nanorods

2016 ◽  
Vol 09 (03) ◽  
pp. 1650039 ◽  
Author(s):  
Jingyuan Piao ◽  
Li-Ting Tseng ◽  
Kiyonori Suzuki ◽  
Jiabao Yi
Keyword(s):  
Magnetic Measurements ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Shallow Donors ◽  
Na Doping ◽  
Transmission Electron ◽  
Doped Zno ◽  
Electron Paramagnetic

Na-doped ZnO nanorods have been fabricated through a hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses indicate that the d spacing of ZnO increases with increasing doping concentration, suggesting the effective incorporation of dopant Na in the samples. Electron paramagnetic resonance (EPR) measurements indicate that there are shallow donors in pure ZnO samples and the shallow donors are strongly prohibited by Na doping. In addition, the resonance at g = 2.005 suggests the formation of Zn vacancies. Magnetic measurements indicate that pure ZnO is paramagnetic and Na doping leads to ferromagnetism at room temperature. Moreover, 0.5% Na-doped ZnO nanorods exhibits the largest saturation magnetization.

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