Structural, Optical, and Magnetic Properties of Cobalt-Doped ZnAl2O4 Nanosheets Prepared by Hydrothermal Synthesis

Nanomaterials with collective optical and magnetic properties are called smart or functional materials and have promising applications in many fields of science and technology. Undoped and Co-doped ZnAl2O4 were prepared using a co-precipitation-assisted hydrothermal method. A systematic investigation was carried out to understand the effects of the Co concentration on the crystalline phase, morphology, and optical and magnetic properties of Co-doped ZnAl2O4. X-ray diffraction confirmed the cubic spinel structure with the Fd3m space group, and there was no impurity phase. X-ray photoelectron spectroscopy of Co-doped ZnAl2O4 confirmed the existence of Zn, Al and O, and the Co in the optimized sample of ZAO-Co-3 confirmed the oxidation state of cobalt as Co2+. Transmission electron microscopy of pure and Co-doped ZnAl2O4 revealed micro-hexagons and nanosheets, respectively. The optical absorption results showed that the bandgap of ZnAl2O4 decreased with increasing Co concentration. The hysteresis loop of Co-doped ZnAl2O4 revealed clear ferromagnetic behavior at room temperature. The as-prepared materials are suitable for energy storage applications, such as in supercapacitors and fuel cells. This work aims to focus on the effect of cobalt ions in different concentrations on structural, optical and magnetic properties.

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The origin of ferromagnetism of Co-doped TiO2 nanoparticles: Experiments and theory investigation

Modern Physics Letters B ◽

10.1142/s0217984916502961 ◽

2016 ◽

Vol 30 (32n33) ◽

pp. 1650296 ◽

Cited By ~ 3

Author(s):

Suyin Zhang ◽

Zhongpo Zhou ◽

Rui Xiong ◽

Jing Shi ◽

Zhihong Lu ◽

...

Keyword(s):

Magnetic Properties ◽

Saturation Magnetization ◽

First Principles ◽

Photoelectron Spectroscopy ◽

Oxygen Vacancies ◽

First Principles Calculation ◽

Ferromagnetic Behavior ◽

X Ray ◽

3D Electron ◽

Co Doped

A series of Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ([Formula: see text] = 0.01, 0.03, 0.05, 0.07) nanoparticles were synthesized by sol–gel method. The X-ray diffraction, transmission electron microscopy, Raman analysis and X-ray photoelectron spectroscopy ruled out the signatures of Ti[Formula: see text], Co-clusters or any other oxides of Co. The ferromagnetic behavior was clearly observed at room temperature in doped samples with saturation magnetization [Formula: see text] of the order of 0.008–0.035 emu/g depending on doping concentrations. The saturation magnetization is found to be increased with the Co contents increasing from 1% to 7%. From the plot of the M–T curve, we obtain the [Formula: see text] as [Formula: see text][Formula: see text]515 K for 5% Co-doped TiO2. Oxygen vacancies were detected from the photoluminescence (PL) measurement. Magnetic properties analyses and PL analyses showed that oxygen vacancies probably played a major role in ferromagnetism of the Ti[Formula: see text]Co[Formula: see text]O2 system with Co substituting for Ti. The first-principles calculation was performed to investigate the magnetic properties of Co-doped TiO2 nanoparticles. It can be found that the major magnetic moment is from the 3d electron of Co. The experiment results are consistent with the first-principles calculation. The ferromagnetism derived from the spin-split of O-2p and Co-3d electron states caused by p–d orbit hybridization.

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EFFECT OF CO-DOPED RARE-EARTH AND TRANSITION-METAL IONS ON STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF BiFeO3 MATERIAL

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/54/1a/11813 ◽

2018 ◽

Vol 54 (1A) ◽

pp. 96

Author(s):

Dao Viet Thang

Keyword(s):

Magnetic Properties ◽

Sol Gel ◽

Transition Metal Ions ◽

Scattering Data ◽

Ferromagnetic Behavior ◽

X Ray Diffraction ◽

X Ray ◽

Optical And Magnetic Properties ◽

Xrd Patterns ◽

Co Doped

Structural, optical and magnetic properties of polycrystalline BiFeO3 and Bi0.9RE0.1Fe0.95Ni0.05O3 (RE = Sm, Y, Nd) prepared by sol–gel method have been investigated. X-ray diffraction (XRD) patterns reveal that all samples crystalize in rhombohedrally distorted perovskite structure belonging to space group R3c. Analyzed results of both XRD and Raman scattering data show an increase of lattice distortion with co-replacing of rare earths and nickel atoms into Bi and Fe sites respectively. All samples exhibit a weak ferromagnetic behavior at room temperature with enhancement of the magnetization of RE and Ni co-doped samples.

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STRUCTURE AND MAGNETIC PROPERTIES OF Co-DOPED SnO2 NANOWIRES

International Journal of Nanoscience ◽

10.1142/s0219581x11008708 ◽

2011 ◽

Vol 10 (04n05) ◽

pp. 967-971 ◽

Cited By ~ 1

Author(s):

U. K. GOUTAM ◽

SHASHWATI SEN ◽

JAGANNATH ◽

A. K. SINGH ◽

R. MUKUND ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Magnetic Measurements ◽

Ferromagnetic Behavior ◽

Tubular Furnace ◽

X Ray Diffraction ◽

X Ray ◽

Co Doping ◽

Sno2 Nanowires ◽

Tin Metal ◽

Co Doped

Co -doped SnO2 nanowires were grown by thermal evaporation of a mixture of Tin metal powder and CoCl2 · 6H2O in a tubular furnace. The growth occurs by vapor–solid growth mechanism. Nanowires grew along the sidewall of the alumina boat placed in the tubular furnace and the diameter of these nanowires (as was evident from scanning electron microscopy), was found to be in the range of 50 nm to 200 nm. Co was successfully doped in SnO2 lattice as revealed by X-ray diffraction data and was found to be in Co2+ state in the nanowires as detected by X-ray Photoelectron Spectroscopy measurements. Room temperature magnetic measurements, carried out using Vibrating Sample Magnetometer, indicated ferromagnetic behavior of the nanowires indicating their potential for spintronics applications. With increasing Co doping (upto 1%), the lattice parameters of SnO2 decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship.

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Structural and magnetic properties of pure and cobalt doped Gallium Nitride nanocrystals

MRS Proceedings ◽

10.1557/proc-1257-o03-37 ◽

2010 ◽

Vol 1257 ◽

Cited By ~ 1

Author(s):

Vottikondala Ganesh ◽

Suresh Sundaram ◽

Krishnan Baskar

Keyword(s):

Magnetic Properties ◽

Gallium Nitride ◽

Magnetic Measurements ◽

Raw Materials ◽

Ferromagnetic Behavior ◽

Secondary Phases ◽

X Ray Diffraction ◽

X Ray ◽

Structural And Magnetic Properties ◽

Co Doped

AbstractIn the present study pure and doped gallium nitride (GaN) nanocrystals were synthesized using gallium trichloride (GaCl3), ethylene diamine tetra acetic acid (EDTA) and cobalt chloride as raw materials at a temperature of 900 °C in ammonia (NH3) atmosphere. The XRD spectrum for pure and cobalt doped GaN nanocrystals shows the formation of single phase wurtzite structure. No impurity phases were observed in the X-ray diffraction pattern for 5% Co doped sample whereas secondary phases were observed when the doping concentration exceeds 5 %. Shift in X-ray diffraction peaks were observed in Co doped samples towards lower angle side compared to pure GaN, it confirms that the Co atoms introduces in to the GaN lattice. Transmission electron microscopy images were taken for pure and Co doped GaN. Hexagonal morphology was observed in pure GaN samples. The average size of the particle was found to be ˜20 nm for pure and Co doped GaN. The magnetic measurements were carried out for the Co (5% & 10%) doped samples both at 10K and 300K. Clear hysteresis loop in the magnetization curve suggest the presence of ferromagnetic behavior in cobalt doped GaN. Temperature dependent magnetization (M-T) measurements were also carried out for doped samples using Super Conducting Quantum Interface Device (SQUID) from 10K to 300K The results have been discussed and correlated to structural and magnetic properties of the materials.

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Structure and Magnetic Properties of (Al, Co) Co-Doped ZnO Thin Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.531-532.299 ◽

2012 ◽

Vol 531-532 ◽

pp. 299-302

Author(s):

Ping Cao ◽

Yue Bai

Keyword(s):

Magnetic Properties ◽

Sol Gel ◽

Ferromagnetic Behavior ◽

X Ray Diffraction ◽

Al Doping ◽

X Ray ◽

Free Carriers ◽

Structural And Magnetic Properties ◽

Co Doped ◽

Main Factor

In this study, Zn0.99Co0.01Al0.015O thin film has been prepared by sol-gel method. The structural and magnetic properties of the sample were investigated. X-ray diffraction spectroscopy analyses indicate that the Co and Al codoping can not disturb the structure of ZnO. No additional peaks are observed in the Zn0.99Co0.01AlxO and Al3+ and Co2+ substitute for Zn2+ without changing the wurtzite structure. The resistance measurements confirm that Al ions increase the free carriers concentration. Based on the above experiments we think the ferromagnetic behavior of the sample could not originate from Co nanoclusters. The presence of free carriers and localized d spins is a prerequisite for the appearance of ferromagnetism. As the result, the carriers generated by Al doping is considered a main factor to induce the ferromagnetic phenomenon.

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Effects of Annealing on Structural and Magnetic Properties of Cobalt Implanted TiO2 Thin Films

MRS Proceedings ◽

10.1557/proc-0999-k05-07 ◽

2007 ◽

Vol 999 ◽

Author(s):

W. Y. Luk ◽

Q. Li ◽

S. P. Wong ◽

H. P. Ho ◽

N. Ke ◽

...

Keyword(s):

Thin Films ◽

Magnetic Properties ◽

Photoelectron Spectroscopy ◽

Rutherford Backscattering Spectrometry ◽

Room Temperature Ferromagnetism ◽

Dose Range ◽

Ion Source ◽

Fixed Dose ◽

X Ray ◽

Co Doped

AbstractSince the observation of room-temperature ferromagnetism (RTFM) in Co-doped anatase TiO2 [1], there have been many reports on the study of the magnetic properties of Co-doped TiO2 prepared by various methods with diversified results. The origin of the RTFM in these systems is still a topic of controversy today. In this work, TiO2 thin films were prepared by RF sputtering onto thermally grown oxide layers on Si substrates. Cobalt implantation was performed using a metal vapor vacuum arc (MEVVA) ion source to various doses ranging from 3×1015 cm-2 to 4×1016 cm-2. Post-implantation annealing was performed in a vacuum chamber at various temperatures ranging from 400°C to 700°C for 2 hours and 4 hours. Characterization of these films as-implanted and after thermal annealing under various conditions was performed using Rutherford backscattering spectrometry, energy filtered and high-resolution transmission electron microscopy, x-ray diffractometry, x-ray photoelectron spectroscopy, and vibrating sample magnetometry. The dependence of the magnetic properties on the implantation and annealing conditions were studied in detail. Clear RTFM properties were observed. The saturation magnetic moment per implanted Co atom (MS) seems to increase with increasing dose within the implantation dose range in this study. At a fixed dose, the MS value also shows a generally increasing trend with increasing annealing temperature and annealing time. Quite a number of samples showed MS values exceeding the bulk Co value of 1.69 ìB/Co significantly and the maximum MS value observed is about 3.16 µB/Co. Such high MS values indicate that the RTFM must not come from Co clusters alone. Possible origins of the RTFM properties will be discussed in conjunction with the structural properties.

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Structural, optical and magnetic properties of Fe-doped CeO2 samples probed using X-ray photoelectron spectroscopy

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-018-9060-x ◽

2018 ◽

Vol 29 (12) ◽

pp. 10141-10153 ◽

Cited By ~ 13

Author(s):

Swati Soni ◽

V. S. Vats ◽

Sudhish Kumar ◽

B. Dalela ◽

Monu Mishra ◽

...

Keyword(s):

Magnetic Properties ◽

Photoelectron Spectroscopy ◽

X Ray ◽

Optical And Magnetic Properties ◽

Doped Ceo2

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Switching in structural, optical, and magnetic properties of self-assembled Co-doped ZnO: effect of Co-concentration

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-013-1623-2 ◽

2013 ◽

Vol 25 (1) ◽

pp. 552-559 ◽

Cited By ~ 4

Author(s):

Richa Bhargava ◽

Prashant K. Sharma ◽

Sushant Singh ◽

Mohit Sahni ◽

Avinash C. Pandey ◽

...

Keyword(s):

Magnetic Properties ◽

Co Concentration ◽

Optical And Magnetic Properties ◽

Doped Zno ◽

Self Assembled ◽

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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X-ray Photoelectron Spectroscopy Analysis of Chitosan–Graphene Oxide-Based Composite Thin Films for Potential Optical Sensing Applications

Polymers ◽

10.3390/polym13030478 ◽

2021 ◽

Vol 13 (3) ◽

pp. 478

Author(s):

Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽

Yap Wing Fen ◽

Silvan Saleviter ◽

Narong Chanlek ◽

Hideki Nakajima ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Functional Group ◽

Optical Sensing ◽

Composite Thin Films ◽

Cobalt Ions ◽

X Ray ◽

Sensing Applications

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.

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