scholarly journals X-ray spectroscopic study of the charge state and local ordering of room-temperature ferromagnetic Mn-doped ZnO

2007 ◽  
Vol 19 (17) ◽  
pp. 172202 ◽  
Author(s):  
J-H Guo ◽  
Amita Gupta ◽  
Parmanand Sharma ◽  
K V Rao ◽  
M A Marcus ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Charge State ◽  
Room Temperature ◽  
X Ray ◽  
Local Ordering ◽  
Doped Zno ◽  
State And Local ◽  
Mn Doped

Formation of ZnO Doped with Mn Thin Film by Electrodeposition and Magnetic Behaviour.

2005 ◽  
Vol 879 ◽  
Author(s):  
M. Abid ◽  
C. Terrier ◽  
J-P Ansermet ◽  
K. Hjort
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetic Behaviour ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doped Zno ◽  
Mn Doped ◽  
Weak Ferromagnetic

AbstractFollowing the theory, ferromagnetism is predicted in Mn- doped ZnO, Indeed, ferromagnetism above room temperature was recently reported in thin films as well as in bulk samples made of this material. Here, we have prepared Mn doped ZnO by electrodeposition. The samples have been characterized by X-ray diffraction and spectroscopic methods to ensure that the dopants are substitutional. Some samples exhibit weak ferromagnetic properties at room temperature, however to be useful for spintronics this material need additional carriers provided by others means.

Effect of PEG on Structural and Magnetic Properties of Mn Doped ZnO Nanocrystals

2013 ◽  
Vol 678 ◽  
pp. 234-238 ◽  
Author(s):  
Vishwanath D. Mote ◽  
Babasaheb N. Dole
Keyword(s):  
Room Temperature ◽  
Magnetic Hysteresis ◽  
Lattice Parameters ◽  
Precipitation Method ◽  
Average Crystalline Size ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Doped Zno ◽  
Co Precipitation ◽  
Mn Doped

Nanosized Mn doped ZnO samples were synthesized by co-precipitation method using Polyethylene glycol (PEG) as a capping agent. X- ray diffraction patterns confirm that the pure and Mn doped ZnO nanocrystals have wurtzite structure without any seconadary phases. Lattice parameters of pure and Mn doped ZnO nanocrystals increase slightly with increasing Mn concentration. The average crystalline size of pure and Mn doped ZnO nanocrystals are in the range of 14-18 nm. The X-ray density for pure and Mn doped ZnO sample is calculated using lattice parameters. It is found that almost static for Mn doped ZnO samples. In the Zn1-xMnx samples, room temperature magnetic hysteresis is observed and the saturation magnetization increases with increasing Mn content. However, these samples show room temperature ferromagnetic in nature. Result of the present investigation compared without PEG.

Room Temperature Ferromagnetism and Fast Ultraviolet Photoresponse of Inkjet-Printed Mn-Doped ZnO Thin Films

2010 ◽  
Vol 46 (6) ◽  
pp. 2152-2155 ◽  
Author(s):  
Yan Wu ◽  
K. V. Rao ◽  
Wolfgang Voit ◽  
Takahiko Tamaki ◽  
O. D. Jayakumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Thin Films ◽  
Doped Zno ◽  
Mn Doped

Structural, Optical and Room Temperature Magnetic Study of Mn-Doped ZnO Nanoparticles

NANO ◽  
2016 ◽  
Vol 11 (04) ◽  
pp. 1650042 ◽  
Author(s):  
Majed Sharrouf ◽  
Ramadan Awad ◽  
Salem Marhaba ◽  
Douaa El-Said Bakeer
Keyword(s):  
Zno Nanoparticles ◽  
Room Temperature ◽  
Xrd Analysis ◽  
Peak Shift ◽  
Antiferromagnetic Coupling ◽  
Ferromagnetic Behavior ◽  
Two Samples ◽  
Doped Zno ◽  
Co Precipitation ◽  
Mn Doped

Undoped and Mn-doped ZnO nanoparticles (Zn[Formula: see text]MnxO), with nominal weight percentages [Formula: see text], have been synthesized by co-precipitation technique. The synthesized nanoparticles are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR). From XRD analysis, the compound ZnMnO3 is formed for [Formula: see text] with cubic structure ([Formula: see text][Formula: see text]Å) and its concentration increases with x. Moreover, XRD analysis reveals the wurtzite hexagonal crystal structure for ZnO. The lattice parameters (a and c) of Zn[Formula: see text]MnxO are calculated and they increase with the doping concentration of Mn as a consequence of the larger ionic size of Mn[Formula: see text] ions compared to Zn[Formula: see text] ions. The crystallite size is calculated for all the samples using Debye–Scherrer’s method (SSM), Williamson–Hall methods (UDM, USDM and UDEDM) and Size-Strain Plot method (SSP), and the results are in good agreement with TEM. The presence of functional groups and the chemical bonding is confirmed by FTIR spectra that shows a peak shift between undoped and doped ZnO. The energy bandgap [Formula: see text] is calculated for different concentrations of Mn [Formula: see text] by using the UV-visible optical spectroscopy, between 300[Formula: see text]nm and 800[Formula: see text]nm, showing a noticeable drop in [Formula: see text] with x. At room temperature, the magnetization of the samples reveals the intrinsic ferromagnetic (FM) behavior of undoped ZnO, ferromagnetic behavior of ZnxMn[Formula: see text]O [Formula: see text] and the co-existence of ferromagnetic and paramagnetic behavior for ZnxMn[Formula: see text]O [Formula: see text]. This ferromagnetism is decreased for the doped samples as a consequence of antiferromagnetic coupling between Mn ions. The two samples correspond to [Formula: see text] and [Formula: see text], tend to be superparamagnetic because of the formation of single domain particles as a consequence of small particle size. [Formula: see text] shows an optimum value of Mn concentration for maximum saturation magnetization and the best ferromagnetic nature.

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 Synthesis, characterization and evaluation of biological activities of manganese-doped zinc oxide nanoparticles

2017 ◽  
Vol 16 (10) ◽  
pp. 2331-2339 ◽  
Author(s):  
Shakeel Ahmad Khan ◽  
Sammia Shahid ◽  
Waqas Bashir ◽  
Sadia Kanwal ◽  
Ahsan Iqbal
Keyword(s):  
Zinc Oxide ◽  
Band Gap ◽  
Zno Nanoparticles ◽  
Butylated Hydroxytoluene ◽  
Total Phenolic ◽  
Spectroscopic Techniques ◽  
Antioxidant Power ◽  
X Ray ◽  
Doped Zno ◽  
Mn Doped

Purpose: To synthesize, characterize and investigate the antimicrobial properties of pure and manganese-doped zinc oxide nanoparticles.Method: Un-doped and manganese-doped zinc oxide (Mn-doped ZnO) nanoparticles were prepared using co-precipitation method. The synthesized Mn-doped ZnO  nanoparticles were characterized using energy-dispersive x-ray spectroscopy  (EDX), scanning electron microscopy (SEM), and x-ray diffraction (XRD)  spectroscopic techniques. Their band gap energies were measured with ultraviolet-visible (UVVis) spectroscopy, while their antioxidant properties were evaluated by ferric reducing antioxidant power (FRAP), DPPH radical-scavenging, ferric  thiocyanate (FTC) and total phenolic content (TPC) assays. The antimicrobial  activities of the nanoparticles against different bacterial strains were determined using agar diffusion method.Result: Results from XRD, SEM, EDX and UV-Vis analyses demonstrated  successful synthesis of undoped and Mn-doped ZnO nanoparticles as seen in their hexagonal, wurtzite structures. The un-doped and Mn-doped ZnO nanoparticles had average grain sizes of 16.72 nm and 17.5 nm, and band gap energies of 3.585 eV and 2.737 eV, respectively. Significant antibacterial activity was manifested by Mndoped ZnO against E. coli, S. aureus, Klebsiella and B. subtilis, with zones of inhibition (ZOIs) of 13 ± 0.09 mm, 14 ± 0.01 mm, 18 ± 0.07 mm and 20 ± 0.10 mm, respectively. The Mn-doped ZnO nanoparticles also exhibited effective and significant antioxidant potential relative to butylated hydroxytoluene (BHT) and un-doped ZnO nanoparticles.Conclusion: Mn-doped ZnO nanoparticles demonstrate significant antimicrobial and antioxidant activities. Thus, the preparation is a good candidate for further development into therapeutic formulations.Keywords: Mn-doped ZnO, Nanoparticles, Properties, Antioxidant, Antibacterial

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