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 ◽  
...  

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.

2009 ◽  
Vol 23 (06) ◽  
pp. 815-824 ◽  
Author(s):  
R. B. ZHAO ◽  
D. L. HOU ◽  
Y. Y. WEI ◽  
Z. Z. ZHOU ◽  
C. F. PAN ◽  
...  

Zn 1-x Fe x O (x = 0.04, 0.06, 0.08, 0.10, 0.12) thin films were grown on Si substrates using reactive magnetron sputtering. X-ray diffraction analyses show that the samples have wurtzite structures with the c-axis orientation. X-ray photoelectron spectroscopy results indicate that the Fe ions are in a +2 charge state in the films. Magnetization measurements indicate that room temperature ferromagnetism is present in films annealed in vacuum while films annealed in air were non-magnetic. The presence of oxygen vacancies in these films may mediate exchange coupling of the dopant ions, resulting in room temperature ferromagnetism.


2014 ◽  
Vol 934 ◽  
pp. 71-74
Author(s):  
Lian Mao Hang ◽  
Zhao Ji Zhang ◽  
Zhi Yong Zhang

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.


RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 62935-62939 ◽  
Author(s):  
Parthasarathi Bera ◽  
Chinnasamy Anandan

X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) investigations of interfacial reactions between Ce and Si have been carried out on as-deposited and 15 month aged CeO2/Si and CeO2/Si3N4 thin films.


2012 ◽  
Vol 05 (04) ◽  
pp. 1250044 ◽  
Author(s):  
G. JAYALAKSHMI ◽  
S. SRIMAN NARAYANAN ◽  
T. BALASUBRAMANIAN

In this paper, we report the activation and deactivation of room temperature ferromagnetism in pure and V doped ZnO ( Zn0.95V0.05O ) films upon surface functionalization with thiol. The thiol functionalized pure ZnO and Zn0.95V0.05O films has been investigated with X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), temperature programmed desorption (TPD) and vibrating sample magnetometer (VSM) measurements. The presence of S 2p3/2 peak about 163.5 eV implies that the formation of Zn-S bonds which in turn leads to the reduction of oxygen vacancies. PL spectra of thiol functionalized pure ZnO and Zn0.95V0.05O films show quenching of visible emission in comparison with the unfunctionalized ZnO films. TPD measurements show that the adsorption of thiol on ZnO surface is stable upto 480 K. On vacuum annealing of the thiol functionalized films above 480 K, desorption starts and gets completely desorbed about 535 K. The room temperature VSM measurements reveal clear signature of ferromagnetic behavior in the functionalized ZnO films. The disappearance of ferromagnetic behavior after vacuum annealing at 550 K confirms the observed ferromagnetic behavior in thiol functionalized ZnO films is due to the strong interaction between the ZnO host and thiol molecules.


2005 ◽  
Vol 475-479 ◽  
pp. 1825-1828
Author(s):  
Ju Hyun Myung ◽  
Nam Ho Kim ◽  
Hyoun Woo Kim

We have demonstrated the growth of ZnO thin films with c-axis orientation at room temperature on various substrates such as Si(100), SiO2, and sapphire by the r.f. magnetron sputtering method. X-ray diffraction (XRD) and scanning electron microscopy altogether indicated that the larger grain size and the higher crystallinity were attained when the ZnO films were deposited on sapphire substrates, compared to the films on Si or SiO2 substrates. The c-axis lattice constant decreased by thermal annealing for the ZnO films deposited on Si or SiO2 substrates, while increased by the thermal annealing for the ZnO films grown on sapphire substrates.


2013 ◽  
Vol 11 (7) ◽  
pp. 1137-1149 ◽  
Author(s):  
Ana Popescu ◽  
Kazimir Yanuskevich ◽  
Olga Demidenko ◽  
Jose Calderon Moreno ◽  
Elena Neacşu ◽  
...  

AbstractThin films of Zn-Ni-P on a copper substrate were synthesized by electrodeposition from chloride baths. It was found that the diffraction reflections of the crystal structure of Zn-Ni-P thin layers occur at thicknesses d ≥ 5 µm. The X-ray diffraction studies results confirm the formation in the Zn-Ni-P films of ZnNi10P3 compound. The morphology of the obtained films was analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The films are continuous and have a typical topography with many homogeneous globular features. EDS confirmed the formation of Zn-Ni-P coating only in 2 samples with Zn:Ni:P atomic ratios of 1:8:4 and 4:8:3, respectively. X-ray Photoelectron Spectroscopy (XPS) revealed the chemistry and the thickness of the studied thin films. At room temperature and thickness d ≥ 5 µm the investigated thin layers exhibit high values of the specific magnetizations in the range (25–37) A m2 kg−1, leading to the potential use in devices, appliances and electronics. The Curie temperature values of the synthesized Zn-Ni-P films were determined. It was found that by heating Zn-Ni-P thin layers of thicknesses d ≥ 5 µm up to a temperature T=900 K an interaction was detected with the copper substrate leading to a lower specific magnetization.


2013 ◽  
Vol 543 ◽  
pp. 277-280
Author(s):  
Marius Dobromir ◽  
Alina Vasilica Manole ◽  
Simina Rebegea ◽  
Radu Apetrei ◽  
Maria Neagu ◽  
...  

Rutile N-doped TiO2thin films were grown by RF magnetron sputtering on amorphous and crystalline substrates at room temperature. The surface elemental analysis, investigated by X-ray photoelectron spectroscopy indicated that the nitrogen content of the films could be adjusted up to values as high as 4.1 at.%. As demonstrated by the X-ray diffraction data, the as-deposited films (100 200 nm thick) showed no detectable crystalline structure, while after successive annealing in air for one hour at 400°C, 500°C and 600°C, the (110) rutile peaks occurred gradually as dominant features. The rutile phase in the films was confirmed by the band gap values of the deposited materials, which stabilized at 3.1 eV, for the thin films having 200 nm thicknesses.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.


Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract


Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.


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