Influence on Doping of 0.4 mol of Co in ZnO Aiming their Application in DMS

2015 ◽  
Vol 820 ◽  
pp. 181-186 ◽  
Author(s):  
Lucius Vinicius Rocha Machado ◽  
L.F. Mouzinho ◽  
M.R. Silva ◽  
E.M.J.A. Pallone ◽  
A.C.F.M. Costa

This paper proposes evaluate the effect on doping of 0.4mol of Co in ZnO, Aiming to use in diluted magnetic semiconductor (DMSs), so for this purpose, an evaluation of the characteristics: structural, morphological and magnetic was investigated. The samples were synthesized by combustion reaction using urea as fuel and an electric heater as source of heating. During the synthesis was performed measurements of temperature and time of combustion flame. The samples were characterized by X-ray diffraction (DRX), adsorption of nitrogen (BET), scanning electron microscopy (SEM), particle size distribution and magnetic measurement. The maximum temperature, and reaction time were, 520 oC and 240 s. The data of the XRD showed how phase majority the ZnO, with crystallite size of 27 nm and trace of second phase CoCo2O4. Presented superficial area of 33.5 m2/g, with morphology consisting of agglomerates in the form of balls smaller than 5 μm. The sample presented behavior ferrimagnetic with saturation magnetization of 0.32 emu/g, type of a magnetic semiconductor.

Cerâmica ◽  
2018 ◽  
Vol 64 (372) ◽  
pp. 627-631
Author(s):  
A. Morais ◽  
R. A. Torquato ◽  
U. C. Silva ◽  
C. Salvador ◽  
C. Chesman

Abstract This work aimed to study a sintered Ni-doped ZnO dilute magnetic semiconductor synthesized by means of a combustion reaction and to evaluate the effect of doping and sintering in the band gap and magnetic properties of the material. X-ray diffraction showed the formation of the ZnO semiconductor phase and also the formation of a second-phase characterized as a solid solution of nickel-zinc oxide. The hysteresis curves showed the success in creating ferromagnetism with doping and the effect of sintering in the remanent magnetization and coercive field values, yet both systems were able to maintain its ferromagnetic behavior. The UV-vis analysis indicated the value of the band gap continued as a semiconductor material, although it has been narrowed. Scanning electron microscopy was used in a complementary way to evaluate the morphology and its effects on magnetic properties.


Author(s):  
A. A. Dakhel

: Anatase (TiO2) nanoparticles co-doped with Ni/Al ions were synthesized by a thermo-precipitation method. The samples were characterized by using X‐Ray diffraction and optical absorption spectroscopy. The structural/optical investigations established the development of substitutional solid solutions: TiO2:Ni:Al. The magnetization investigations were performed to study the generated stable ferromagnetic properties of the samples due to the Ni2+ doping. To boost the created ferromagnetic properties, Al ions co-dopings were employed to supply/densify the itinerant electrons. It was planned to decide the suitable hydrogenation conditions and temperature (TH), which are necessary to create appreciable strength of ferromagnetic properties in the host co-doped samples based on TiO2 for practical uses. The results established that the ferromagnetic energy (Umag) was increased by ~240% and the saturation magnetization by ~140% with increasing of TH from 400 oC to 500oC. The obtained Msat was higher by ~50 times than that previously attained for Ni-doped TiO2. Such novel results were discussed and explained through the spin-spin Heisenberg interactions.


2012 ◽  
Vol 727-728 ◽  
pp. 511-515 ◽  
Author(s):  
R. Torquato ◽  
E. Shirsath Sagar ◽  
Ruth Herta Goldsmith Aliaga Kiminami ◽  
Ana Cristina Figueiredo de Melo Costa

ZnO is a semiconductor that can be doped with transition metal ions, and thus becomes feasible to use in the diluted magnetic semiconductor (DMS), or semiconductor with magnetic properties. In this work we have studied the influence of doping of Ni+2on the structural, morphological and magnetic properties of Zn1-xNixO system, to x = 0.07, 0.1 and 0.2 mol of Ni+2synthesized by combustion reaction. The systems were characterized by XRD, SEM and VSM. The maximum temperatures ranged from 639 K and 683 K. All systems showed a majority phase formation of ZnO, with the presence of the second phase NiO. The crystallite size for the majority phase varied between 49 and 56nm. All systems have resulted in samples with a morphology consisting of dense clusters, formed by particles pre-sintered and shaped roughly hexagonal plates. The magnetic measurements showed that the values of saturation magnetization lies between 4.6 to 28.5emu/g, remanent magnetization of 0.01 to 0.3 emu/g, coercive force values varies between 12.7 and 62.4 Oe and Curie temperature ranging from 308 to 311K.


2009 ◽  
Vol 615-617 ◽  
pp. 461-464 ◽  
Author(s):  
Alain Declémy ◽  
Cyril Dupeyrat ◽  
Lionel Thomé ◽  
Aurelien Debelle

Silicon carbide (SiC) could be a good candidate for Diluted Magnetic Semiconductor (DMS). In this paper we report on preliminary results on the microstructure of Fe-implanted 6H-SiC subsequently submitted to Rapid Thermal Annealing (RTA), laser processing in the solid phase and swift heavy ion irradiation and analyzed by means of X-ray diffraction (XRD) and Rutherford backscattering and channeling (RBS/C).


2008 ◽  
Vol 591-593 ◽  
pp. 387-391
Author(s):  
Lucianna Gama ◽  
M.A. Ribeiro ◽  
Débora A. Vieira ◽  
A.M.C. Santos ◽  
Ruth Herta Goldsmith Aliaga Kiminami ◽  
...  

Diluted magnetic semiconductors (DMS), which have both semiconducting and magnetic properties, are those in which transitions metal ions substitute cations of host semiconductor materials [1]. There is a great interest for DMS for use as the material of spintronics. In this study is reported the structural and morphologic characterization of Zn1.95Co0.05O nanoparticles obtained by Pechini method and combustion reaction. The powders resulting were characterized by X-ray diffraction (XRD) for determination of the phases, crystalline phase and lattice parameter; nitrogen adsorption by BET for determination of the specific superficial area and calculation the particle size from the superficial area and scanning electron microscopy (SEM) for morphologic analysis. The XRD results demonstrated the viability of obtaining crystalline and nanosize powders by the both synthesis routes. For all samples the average crystallite sizes was nanosized, but the powders obtained by reaction combustion is smaller. The SEM micrographs shows that the powders obtained for both syntheses are constituted of soft agglomerates.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Xiaolu Liang ◽  
Xianhua Wei ◽  
Daocheng Pan

Diluted magnetic semiconductorCu2FeSnS4nanocrystals with a novel zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+ions occupy the same position in the zincblende unit cell, and their occupancy possibilities are 1/2, 1/4, and 1/4, respectively. The nanocrystals were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), and UV-vis-NIR absorption spectroscopy. The nanocrystals have an average size of 7.5 nm and a band gap of 1.1 eV and show a weak ferromagnetic behavior at low temperature.


2015 ◽  
Vol 760 ◽  
pp. 329-334
Author(s):  
Madalin Ion Rusu ◽  
Daniel Tenciu ◽  
Nicolae Catalin Zoita ◽  
Roger Notonier ◽  
Alain Tonetto ◽  
...  

Bulk polycrystalline MnGexSby materials doped with Co or Fe were prepared and investigated with the aim of obtaining new diluted magnetic semiconductor (DMS) materials. An innovative preparation method was also established. Investigation techniques like X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM) associated with energy dispersive X-ray analysis (EDX) have been employed to derive the structural properties and the composition of the bulk material.


1993 ◽  
Vol 84 (4) ◽  
pp. 633-636 ◽  
Author(s):  
K. Ławniczak-Jabłońska ◽  
Z. Gołacki ◽  
W. Paszkowicz ◽  
R.J. Iwanowski ◽  
L.S. Johansson ◽  
...  

2013 ◽  
Vol 543 ◽  
pp. 251-254 ◽  
Author(s):  
Soumia Lardjane ◽  
Mohammad Arab Pour Yazdi ◽  
Noureddine Fenineche ◽  
G. Merad ◽  
H.I. Feraoun ◽  
...  

Zn1-xCoxO (0 < x < 14.6) diluted magnetic semiconductor coatings have been obtained by reactive DC magnetron sputtering of metallic Zn and Co targets at high pressure and high temperature. The coatings structural properties have been investigated by X-ray diffraction. All as-deposited coatings are crystalized in ZnO structure and neither traces of metallic nor oxide Co-rich clusters were detected in the films. The temperature dependence of the magnetization shows a paramagnetic Curie-Weiss behavior with antiferromagnetic interaction due to the associated spins and simple paramagnetic curie behavior of isolated free spins.


Cerâmica ◽  
2020 ◽  
Vol 66 (379) ◽  
pp. 262-268
Author(s):  
D. B. Maia ◽  
R. A. Raimundo ◽  
T. A. Passos ◽  
R. A. Torquato

Abstract Eu-doped semiconductor matrix of ZnO at concentrations of 0.05 and 0.10 mols was synthesized by combustion reaction, using zinc nitrate, europium nitrate, and urea as fuel. In order to analyze the effect of europium concentration and sintering on the structure, band gap, magnetic and morphological properties of ZnO, the samples were sintered at 1100 °C for 30 min and analyzed before and after sintering via X-ray diffraction, ultraviolet and visible spectroscopy, vibrant sample magnetometry, and scanning electron microscopy. From the results obtained, it was found that there was the formation of the semiconductor phase ZnO and also a second-phase (Eu2O3). It was observed that the samples before and after sintering presented band gap values within the semiconductor range and ferromagnetism at room temperature.


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