Co doped ZnO semiconductor materials: structural, morphological and magnetic properties

AbstractStructural, morphological and magnetic properties of Zn1−xCoxO (x = 0.01 and 0.03) powdered materials are presented. XRD studies reveal a wurtzite-type structure, while the formation of a Co3O4 secondary phase was evidenced by Raman spectroscopy. A ferromagnetic behaviour with low Curie temperature was evidenced by Electron Paramagnetic Resonance (EPR) investigation. We suggest that the origin of the ferromagnetism in Zn1−xCoxO powders is probably due to the presence of the mixed cation valence of Co ions via a double-exchange mechanism rather than the real doping effect.

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ROOM TEMPERATURE FERROMAGNETISM IN Mn DOPED ZnO SEMICONDUCTOR

International Journal of Modern Physics B ◽

10.1142/s0217979209052133 ◽

2009 ◽

Vol 23 (08) ◽

pp. 2029-2040 ◽

Cited By ~ 3

Author(s):

R. K. SINGHAL ◽

S. N. DOLIA ◽

M. S. DHAWAN ◽

S. K. GAUR ◽

SUDHISH KUMAR ◽

...

Keyword(s):

Magnetic Properties ◽

Room Temperature ◽

Room Temperature Ferromagnetism ◽

Recent Past ◽

Doped Zno ◽

Ferromagnetic Ordering ◽

Mn Doped ◽

Zno Semiconductor ◽

Ferromagnetic Contribution ◽

Co Doped

Following the theoretical prediction of ferromagnetism in Mn - and Co -doped ZnO , there has been an immense experimental search for dilute semiconductors that show ferromagnetic ordering above room temperature, and several workers have reported ferromagnetism in bulk samples as well as in thin films of these materials. Mn -doped ZnO is the key material in this regard, which has been, in the recent past, shown to exhibit such magnetic properties. Many more such attempts have either led to failure or to a much lower Tc, and there have been a lot of confronting reports casting considerable doubts on the magnetism in this system. In order to shed some light, we have prepared and characterized dilute Mn -doped (2 and 4%) ZnO pellets. SQUID measurements confirm that the 2% sample shows above room temperature ferromagnetic ordering, the ferromagnetic contribution coming mainly from the bulk. The ordering gets completely quenched for 4% Mn doping. Upon cooling down, the 2% Mn doped sample showed further enhancement in magnetic properties appreciably. On the other hand, the 4% sample did not show any ferromagnetic ordering, even down to 5 K, and has been found to retain the paramagnetic character.

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Electron Paramagnetic Resonance Characterization of Mn- and Co-Doped ZnO Nanowires

10.1063/1.2729771 ◽

2007 ◽

Cited By ~ 1

Author(s):

A. O. Ankiewicz ◽

W. Gehlhoff ◽

E. M. Kaidashev ◽

A. Rahm ◽

M. Lorenz ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Zno Nanowires ◽

Paramagnetic Resonance ◽

Doped Zno ◽

Electron Paramagnetic ◽

Co Doped

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Magnetic Properties, Electron Paramagnetic Resonance, and Photoelectron Spectroscopy Studies of Nanocrystalline TiO 2 Co‐Doped with Al and Fe

physica status solidi (b) ◽

10.1002/pssb.202000399 ◽

2020 ◽

pp. 2000399 ◽

Cited By ~ 1

Author(s):

Anatoly Ye. Yermakov ◽

Vadim R. Galakhov ◽

Artem S. Minin ◽

Vitaly V. Mesilov ◽

Mikhail A. Uimin ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Magnetic Properties ◽

Photoelectron Spectroscopy ◽

Paramagnetic Resonance ◽

Spectroscopy Studies ◽

Electron Paramagnetic ◽

Co Doped

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Influence of N Dopant on the Electric and Magnetic Properties of Co Doped ZnO Thin Films

Journal of Inorganic Materials ◽

10.3724/sp.j.1077.2010.00711 ◽

2010 ◽

Vol 25 (7) ◽

pp. 711-716 ◽

Cited By ~ 3

Author(s):

Xue-Tao WANG ◽

Li-Ping ZHU ◽

Zhi-Gao YE ◽

Zhi-Zhen YE ◽

Bing-Hui ZHAO

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Zno Thin Films ◽

Doped Zno ◽

Co Doped

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Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

Current Nanoscience ◽

10.2174/1573413715666191010162626 ◽

2020 ◽

Vol 16 (4) ◽

pp. 655-666

Author(s):

Mona Rekaby

Keyword(s):

Magnetic Properties ◽

Zno Nanoparticles ◽

Room Temperature ◽

Magnetic Measurements ◽

Structural Defects ◽

Ferromagnetic Behavior ◽

Secondary Phases ◽

Antiferromagnetic Ordering ◽

Doped Zno ◽

Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

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Monitoring of the Mechanism of Mn Ions Incorporation into Quantum Dots by Optical and EPR Spectroscopy

Photonics ◽

10.3390/photonics6040107 ◽

2019 ◽

Vol 6 (4) ◽

pp. 107

Author(s):

Yuriy G. Galyametdinov ◽

Dmitriy O. Sagdeev ◽

Andrey A. Sukhanov ◽

Violeta K. Voronkova ◽

Radik R. Shamilov

Keyword(s):

Electron Paramagnetic Resonance ◽

Magnetic Properties ◽

Luminescent Properties ◽

Manganese Concentration ◽

Manganese Ions ◽

Paramagnetic Resonance ◽

Synthesis Of Nanoparticles ◽

Zinc Sulfide Nanoparticles ◽

Optical And Magnetic Properties ◽

Electron Paramagnetic

Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.

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Electrospun Nanosystems Based on PHBV and ZnO for Ecological Food Packaging

Polymers ◽

10.3390/polym13132123 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2123

Author(s):

Maria Râpă ◽

Maria Stefan ◽

Paula Popa ◽

Dana Toloman ◽

Cristian Leostean ◽

...

Keyword(s):

Food Packaging ◽

Spin Trapping ◽

X Ray Diffraction ◽

Paramagnetic Resonance ◽

Hno3 Solution ◽

X Ray ◽

Trapping Method ◽

Ft Ir ◽

Doped Zno ◽

Electron Paramagnetic

The electrospun nanosystems containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and 1 wt% Fe doped ZnO nanoparticles (NPs) (with the content of dopant in the range of 0–1 wt% Fe) deposited onto polylactic acid (PLA) film were prepared for food packaging application. They were investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), antimicrobial analysis, and X-ray photoelectron spectrometry (XPS) techniques. Migration studies conducted in acetic acid 3% (wt/wt) and ethanol 10% (v/v) food simulants as well as by the use of treated ashes with 3% HNO3 solution reveal that the migration of Zn and Fe falls into the specific limits imposed by the legislation in force. Results indicated that the PLA/PHBV/ZnO:Fex electrospun nanosystems exhibit excellent antibacterial activity against the Pseudomonas aeruginosa (ATCC-27853) due to the generation of a larger amount of perhydroxyl (˙OOH) radicals as assessed using electron paramagnetic resonance (EPR) spectroscopy coupled with a spin trapping method.

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