Effect of iron doping concentration on magnetic properties of ZnO nanoparticles

Sharma, Prashant K.; Dutta, Ranu K.; Pandey, Avinash C.; Layek, Samar; Verma, H. C.

doi:10.1016/j.jmmm.2009.03.043

Cited by 113 publications

(48 citation statements)

References 14 publications

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“…These results were again contrasting, where some researchers observed ferromagnetic ordering at lower doping concentration but paramagnetic behavior for higher doping concentration. For iron doping, it was explained that paramagnetic behavior is due to antiferromagnetic coupling at higher doping concentration [11,[18][19][20]. In our cobalt-doped samples, a cobalt proportional ferromagnetic strength was observed due to different electronic configurations of cobalt and agglomeration of a little fraction of cobalt atoms (as revealed by XRD) which prevents anti-ferromagnetic coupling.…”

Section: Xrd Graphs Of Doped Zno Nano-particles (Shown Inmentioning

confidence: 62%

Effect of doping concentration on absorbance, structural, and magnetic properties of cobalt-doped ZnO nano-crystallites

et al. 2012

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Controlled conduction of magnetic spins is desired for data processing in modern spintronic devices. Transition metal-doped ZnO is a potential candidate for this purpose. We studied the effects of cobalt doping on structural, absorbance, and magnetic properties of ZnO nano-particles. Different compositions (Zn 0.99 Co 0.1 O, Zn 0.97 Co 0.3 O, and Zn 0.95 Co 0.5 O) of cobalt-doped ZnO were fabricated using metallic chlorides by co-precipitation method. XRD revealed standard ZnO wurtzite crystal structure without lattice distortion due to impurities but showed presence of additional phases at higher doping ratios. Fourier transformed infrared spectroscopy also confirmed the standard ZnO profiles at lower doping ratios but additional phases at higher doping. Vibrating sample magnetometer showed soft ferromagnetic behavior for low impurity samples and harder ferromagnetic behavior for higher doping at room temperature. A simultaneous differential scanning calorimetry/thermo gravimetric analysis was performed to study the phase variations during crystallization.

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Section: Xrd Graphs Of Doped Zno Nano-particles (Shown Inmentioning

confidence: 62%

Effect of doping concentration on absorbance, structural, and magnetic properties of cobalt-doped ZnO nano-crystallites

et al. 2012

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“…As an important n-type semiconductor material, ZnO has received extensive attention because of its remarkable optical, magnetic, and electrical properties [2][3]. The doping of transition metal elements is one of the most important methods to modify the electronic structure and characteristics of the host material [4][5]. Among all of the transition metals, Co has been frequently employed because of its variable oxidation state, large magnetic and high solubility limit in ZnO.…”

Section: Introductionmentioning

confidence: 99%

Effect of annealing time and annealing atmosphere on infrared emissivity property of Zn1-xCoxO by solid state reaction

Zhu¹,

Tan²,

Xu³

et al. 2017

Proceedings of the 2017 2nd International Conference on Materials Science, Machinery and Energy Engineering (MSMEE 2017)

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The Zn 1-x Co x O powders were synthesized by solid-state reaction at different annealing time and annealing atmosphere. The effects of annealing time and annealing atmosphere on the structure, morphologies and infrared emissivities have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy and IR-2 dual-band infrared emissometer. The results indicate that the Zn 1-x Co x O samples have hexagonal wurtzite structure while the peaks of the secondary phase, Co, were observed when sintering at N 2 atmosphere. The annealing time and annealing atmosphere have important impacts on the microstructure and the infrared radiation properties of Zn 1-x Co x O nanopowders. UV-visible absorption spectra showed that Co ions substituted the Zn ions in the ZnO lattices. And the infrared emissivity depends on the microstructure, grain size and lattice vibration.

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“…Dietl et al [4] and Sato et al [5] predicted that, the transition metal ions doped ZnO are the promising candidates for spintronics applications with intrinsic DMS properties at RT. In this context transition metal doped ZnO DMS's are being extensively studied in the form of both nanoparticles [6][7][8][9][10] and thin films [11][12][13][14][15][16][17] by various research groups. Co doped ZnO based DMS materials are of great interest, due to the tunability of FM above RT, high solubility limit and large magnetic moment per 'Co' ion.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical calculations by Sako and Katayama-Yoshida [5], have predicted that intrinsic FM of Co doped ZnO can be achieved by electrondoping, when magnetic dopants substituted at 'Zn' cation sites. There are few reports with experimental results on Co doped ZnO with DMS properties [6][7][8][9][10][11][12][13][14][15][16][17]. But the possibilities of extrinsic FM have not been ruled out, in fact it has been observed in Co doped ZnO [18][19][20][21], due to the formation of metallic Co impurity, Co 3 O 4 phases and oxygen vacancies.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

Srinatha

Angadi

Nair

et al. 2014

Journal of Electron Spectroscopy and Related Phenomena

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a b s t r a c tPure and Co substituted ZnO nano crystalline particles were prepared by solution combustion technique using l-Valine as a fuel. As synthesized powder samples were characterized by X-ray diffractometer and SQUID magnetometer to confirm the formation of single phase wurtzite structure and to study the bulk magnetic response of the sample, respectively. Magnetic studies show that Co doped ZnO nanoparticles exhibit ferromagnetism (FM) at room temperature (RT). Furthermore, the electronic structure and element specific magnetic properties were investigated by near-edge X-ray absorption fine structure (NEXAFS) and X-ray magnetic circular dichroism (XMCD) measurements, respectively. The effect of Co substitution on the spectral features of Co-ZnO at O K-edge, Co L 3,2 edge, Zn L 3,2 edge have been investigated. The spectral features of NEXAFS at Co L 3,2 edge is entirely different from the spectral features of metallic clusters and other impurity phases, which rules out the presence of impurity phases. The valence state of 'Co' ion is found to be in +2 state. The FM nature of the sample was confirmed through XMCD spectra, which is due to the incorporation of divalent 'Co' ions. Hence the presented results confirm the substitution of 'Co' ions at 'Zn' site in the host lattice, which is responsible for the RTFM.

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Effect of iron doping concentration on magnetic properties of ZnO nanoparticles

Cited by 113 publications

References 14 publications

Effect of doping concentration on absorbance, structural, and magnetic properties of cobalt-doped ZnO nano-crystallites

Effect of doping concentration on absorbance, structural, and magnetic properties of cobalt-doped ZnO nano-crystallites

Effect of annealing time and annealing atmosphere on infrared emissivity property of Zn1-xCoxO by solid state reaction

Spectroscopic investigation of an intrinsic room temperature ferromagnetism in Co doped ZnO nanoparticles

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