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.

Synthesis and Photoluminescence of Cr-Doped Rod-Like ZnO Particles by Hydrothermal Method

2011 ◽  
Vol 306-307 ◽  
pp. 176-179 ◽  
Author(s):  
Lian Mao Hang ◽  
Zhi Yong Zhang ◽  
Jun Feng Yan
Keyword(s):  
Hydrothermal Method ◽  
Room Temperature ◽  
Blue Emission ◽  
Hexagonal Wurtzite Structure ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Zno Particles ◽  
Strong Blue Emission

Cr-doped rod-like ZnO particles with nominal 3 at% doping concentration were synthesized by hydrothermal method. The structural and optical properties of the sample were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and photoluminescence (PL). The results show that the as-synthesized product is of hexagonal wurtzite structure without metallic Cr or other secondary phases and the morphology of the ZnO particles is rod shaped. The room-temperature PL spectrum of the Cr-doped rod-like ZnO particles exhibits a strong blue emission at 440nm and two weak emission bands centered at 410nm and 565nm, respectively.

Preparation of Coral-Like α-Fe2O3 Nanostructures and Magnetic Properties

2011 ◽  
Vol 194-196 ◽  
pp. 625-628
Author(s):  
Hong Wang ◽  
Min Gong ◽  
Jing Yu Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Ferromagnetic Behavior ◽  
Average Thickness ◽  
Solvothermal Process ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Coral-like α-Fe2O3nanostructures modified by surfactant CTAB have been successfully obtained via a solvothermal process by using FeCl36H2O and oxalic acid as the starting materials. The coral-like α-Fe2O3nanostructures with good-crystalline consist of well-aligned α-Fe2O3nanoflakes with an average thickness of about 40 nm growing radially from the center of the nanostructures. The obtained products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), superconducting quantum interference device magnetometer (SQUID). Magnetic hysteresis measurements indicate that coral-like α-Fe2O3superstructures show a normal ferromagnetic behavior with the remanence and coercivity of 0.2346emu/g and 1862Oe at room temperature. CTAB, the reaction temperature and solvent played an important role in controlling the final morphology of the products.

Hydrothermal Synthesis, Photoluminescence and Room Temperature Ferromagnetism of Co-Doped Rod-Like ZnO Particles

2014 ◽  
Vol 633-634 ◽  
pp. 292-295
Author(s):  
Lian Mao Hang ◽  
Zhi Yong Zhang
Keyword(s):  
Quantum Interference ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Blue Emission ◽  
Diffraction Field ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
Violet Emission ◽  
Zno Particles ◽  
Co Doped

Co-doped rod-like ZnO particles with nominal Co doping concentration of 1 at% were synthesized by hydrothermal method and characterized by X-ray diffraction, field-emission scanning electron microscopy, photoluminescence and superconducting quantum interference device. The results show that the as-synthesized samples are pure hexagonal wurtzite structure without metallic Co or other secondary phases and display rod-like shape with smooth surface. The room temperature PL spectrum of the Co-doped rod-like ZnO particles exhibits a strong blue emission at 440 nm, a shoulder violet emission at 410 nm and a weak green emission centered at 550 nm. The magnetization measurements reveal that the Co-doped rod-like ZnO particles show ferromagnetic behavior at room temperature. The saturation magnetization and coercive field are 0.0125 emu/g and 45 Oe, respectively.

ROOM-TEMPERATURE FERROMAGNETIC PROPERTIES OF Co-DOPED ZnO NAOROD ARRAYS

2013 ◽  
Vol 27 (15) ◽  
pp. 1362010 ◽  
Author(s):  
C. L. ZHANG ◽  
C. G. HU
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Ferromagnetic Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Polarized Electrons ◽  
Spin Polarized ◽  
Doped Zno ◽  
Zinc Foils ◽  
Co Doped

Co -doped ZnO rod arrays were fabricated on zinc foils by a hydrothermal method. X-ray diffraction results indicate that the samples have wurtzite crystalline structure without metallic Co or other secondary phases detected. The nanorod arrays exhibit room-temperature ferromagnetic behavior for different Co concentration. The influence of Co on the magnetic properties of ZnO was studied by the first-principles calculations. The exchange interaction between local spin-polarized electrons and conductive electrons is proposed as a cause of the room-temperature ferromagnetism.

scholarly journals The Intrinsic Room-Temperature Ferromagnetism in ZnO:Co Thin Films Deposited by PLD

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
C. C. Wang ◽  
B. Y. Man ◽  
M. Liu ◽  
C. S. Chen ◽  
S. Z. Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Intrinsic Property ◽  
Ferromagnetic Behavior ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates

c-axis preferential orientated ZnO:Co thin films were synthesized onc-plane sapphire substrates by using pulsed laser deposition (PLD) technique in an oxygen-deficient ambient. X-ray diffraction spectra, scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, UV-vis transmittance spectra, and Raman spectra were used for characterization. Ferromagnetic behavior was clearly observed at room temperature and verified to be the intrinsic property of the material. The presence of second phase was ruled out.

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.

Structural and Magnetic Properties of Cobalt and Aluminum Co-Doped ZnO Powders

2008 ◽  
Vol 47-50 ◽  
pp. 600-603
Author(s):  
Yan Yan Wei ◽  
Deng Lu Hou ◽  
Rui Bin Zhao ◽  
Zhen Zhen Zhou ◽  
Cong Mian Zhen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Ferromagnetic Behavior ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Al Content ◽  
Infrared Reflection ◽  
Zno Powders ◽  
Ft Ir

A series of Zn0.95-xCo0.05AlxO (x=0, 0.01, 0.02, 0.05, 0.08, 0.10) powders with different percentages of aluminum was fabricated using the sol-gel method. X-ray diffraction (XRD) revealed that the Co ions and Al ions substitute for Zn2+ ions without changing the wurtzite structure. No impurity phases were found. No clusters or precipitates of cobalt or aluminum were found using scanning electron microscope analysis. Fourier transform-infrared reflection (FT-IR) spectrometry was used to examine the infrared transmission properties and revealed that Co ions were incorporated into the lattice as Co2+ substituting for Zn2+. Ferromagnetic behavior in the samples was obtained at room temperature. As the Al content x increased, the room temperature ferromagnetism of the samples was reduced, and when x increased to 0.08, the room temperature ferromagnetism disappeared.

Room Temperature Ferromagnetism and its "Switch" Behaviour in some Dilute Magnetic Oxides: an Electronic Structure and Magnetization Study

2011 ◽  
Vol 171 ◽  
pp. 19-38 ◽  
Author(s):  
R.K. Singhal
Keyword(s):  
Electronic Structure ◽  
Quantum Interference ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Diluted Magnetic Semiconductor ◽  
Room Temperature Ferromagnetism ◽  
Secondary Phase ◽  
X Ray ◽  
Two Samples ◽  
Doped Zno

ZnO doped with a few per cent of magnetic ions such as Ni, Fe, Co exhibits room temperature ferromagnetism (RTFM), transforming it into a very promising candidate for future spintronic applications. Two samples i.e. ZnO doped with Ni and Cr (5% each) have been investigated in the present work. The samples were characterized by Rietveld refinement of X-ray diffraction (XRD) patterns and the superconducting quantum interference device (SQUID) magnetometry. Rietveld analysis confirms that both the polycrystalline samples possess wurtzite structure with no evidence of any secondary phase. The SQUID measurements exhibit a diamagnetic state for the pristine ZnO and a paramagnetic state for the as-synthesized (Cr and Ni)-doped ZnO samples. However, the post annealing in H2 and vacuum drive them to a remarkable ferromagnetic state at room temperature. No element specific signature for ferromagnetism was seen. Then the X-ray photoelectron spectroscopic (XPS) measurements were performed to investigate their electronic structure and exploring the origin of ferromagnetism in these diluted magnetic semiconductor materials. The XPS results confirm the creation of oxygen vacancies upon Hydrogen/ vacuum annealing, owned to the (Ni/Cr) 3d¬−O 2p hybridization. The findings suggest oxygen vacancies as the intrinsic origin for ferromagnetism in doped ZnO. The important feature of this work is that the ferromagnetism and the consequent electronic property changes are found to be reversible with regard to re-heating the samples in air, showing a switch “on” and “off” ferromagnetic ordering in the ZnO matrix.

scholarly journals Structural and magnetic properties of mechanochemically synthesized nanosized yttrium titanate

2012 ◽  
Vol 66 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Tanja Barudzija ◽  
Alexey Gusev ◽  
Dragana Jugovic ◽  
Milena Marinovic-Cincovic ◽  
Miroslav Dramicanin ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Single Phase ◽  
High Energy ◽  
Argon Atmosphere ◽  
Molar Ratio ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Mean ◽  
First Time

Nanosized perovskite YTiO3 with the mean crystallite size of 18 nm was synthesized for the first time by mechanochemical treatment. The mechanochemical solid state reaction between commercial Y2O3 powder and mechanochemically synthesized TiO powder in molar ratio 0.5:1 was completed for 3 h in a high-energy planetary ball mill in argon atmosphere. The heating in vacuum at 1150 ?C for 12 h transforms nanosized YTiO3 to a well-crystallized single-phase perovskite YTiO3. Both samples were characterized by X-ray diffraction (XRD) and thermogravimetric (TGA/DTA) analyses, as well as superconducting quantum interference device magnetometer (SQUID) measurements.

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.

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