Magnetic properties of Fe doped, Co doped, and Fe+Co co-doped ZnO

Beltrán, J. J.; Osorio, J.; Barrero, C. A.; Hanna, Charles B.; Punnoose, Alex

doi:10.1063/1.4799778

Cited by 70 publications

(26 citation statements)

References 26 publications

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“…7 shows a wasp-waist M-H plots (at 300 o C) which might have been observed due to hole mediated exchange interaction [4]. Ferromagnetic behaviour arises here due to introduction of hole by the exchange of Co 2+ ions with Zn site in Co doped ZnO [26]. Because of appearance of hole charge transfer results in additional charge from the dopant, which results in magneto-electronic coupling.…”

Section: Introductionmentioning

confidence: 92%

Effect of Calcination on Structural and Magnetic Properties of Co-Doped ZnO Nanostructures

et al. 2015

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Diluted magnetic semiconductors have gained much interest in spintronics due to the involvement of both spin and charge. Among various diluted magnetic semiconductors ZnO, lightly doped with transition metals (Mn, Fe, Co, Ni, In, V, and Cr), has gained interest due to the presence of room temperature ferromagnetism. Amongst various dopants, cobalt is a potential candidate because its ionic radius (Co 2+ =0.58Å) is extremely close to zinc (Zn 2+ =0.6Å). Zinc acetate dihydrate and cobalt nitrate are used as precursor materials. Nanostructures are synthesized at a low temperature of 70˚C. The dopant concentration is varied as 1, 3, 5, 7 and 9wt. %. XRD results indicate formation of hexagonal wurtzite structure even under as-synthesized conditions. Crystallite size decreases from 22.7nm to 17.8nm as dopant concentration was increased in the range 0-7wt%. XRD of the samples with 7wt% Co concentration is calcined in the temperature range of 100-500°C. SEM images show nanostructures with grain size less than 50nm. Saturation magnetization increases from 5.07emu/g to 6.4emu/g as dopant concentration was increased to 7wt% under as synthesized conditions. Nanostructures calcined at 400˚C show highest saturation magnetization of 9.9emu/g. Magnetic hysteresis equivalent to that of multilayered structure is obtained after calcination of Co doped ZnO nanoparticles at 300 °C. Single layer of these synthesized Co doped ZnO can be used instead of complex structures in spintronic devices.

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Section: Introductionmentioning

confidence: 92%

Effect of Calcination on Structural and Magnetic Properties of Co-Doped ZnO Nanostructures

et al. 2015

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“…It is worth mentioning that, in a stoichiometric wurtzite structure, the c/a ratio is 1.633. Here, all of the samples showed a significantly smaller c/a ratio (1.601±0.001), and this might indicate the presence of V O and extended defects [19]. As for the ZF2 samples annealed at different T A , the lattice parameters and the cell volume of the ZF2-600 and ZF-700 samples are higher than those of the ZF2-500 sample, as shown in Table 1.…”

Section: A X-ray Diffraction Analysismentioning

confidence: 77%

Effects of Annealing Temperature and Dopant Concentration on the Structural, Optical, and Magnetic Properties of Iron-Doped ZnO Samples

2017

Aug. 2017 Thailand International Conferences BackICMBPS-17, ICCSIT-17, LHEBC-17, IETCIA-17, ICBEFS-17, CM3E-17, AHSS-17, CBCE-1

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This paper reports on the structural, optical, and magnetic properties of as-prepared and annealed Zn 1-x Fe x O (0.02≤x≤0.08) powders synthesized using the solid-state reaction method. X-ray diffraction (XRD) studies showed that Fe was incorporated into the ZnO lattice. Ultraviolet-Visible (UV-vis) spectrophotometry measurements revealed that the bandgap initially increased and then decreased with Fe doping. Photoluminescence (PL) studies confirmed the formation of oxygen vacancies (V O) in all of the samples. All of the samples exhibited ferromagnetic behavior at room temperature (RT). Ferromagnetic behavior decreased with increased Fe concentrations, due to the increase in the number of Fe atoms occupying the neighboring cation lattice sites, which resulted in an antiferromagnetic configuration. Ferromagnetic behavior also decreased with the increase in the annealing temperature (T A) due to the reduction of defects and/or V O. However, our results indicate that the ferromagnetic property is intrinsic to the ZnO system due to defects and/or V O , and the extrinsic impurity origin was excluded..

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“…It was established that the observed ferromagnetic effect was related to the mutual substitution of Zn 2+ and Co 2+ ions in the lattice sites of ZnO grains. Li doped sam ples exhibited only paramagnetic properties, but a combination of Li and Co increased the saturation magnetization from 7.1 to 9.5 G. Experimental study [24] of the nanodispersed structures with composi tions ZnO 0.95 Co 0.05 O, ZnO 0.95 Fe 0.05 O, and ZnO 0.9 Co 0.05 Fe 0.05 O obtained by the sol-gel method showed that the simultaneous doping with two metal ions (Co 2+ , Fe 2+ ) led to several fold increase in the manifestation of ferromagnetic properties.…”

Section: Ferromagnetism Of Varistor Ceramicsmentioning

confidence: 89%

Specific features of thermal phonon scattering and ferromagnetic properties of ZnO varistor ceramics

Kopylov

Таранов

Хазанов

2014

J. Exp. Theor. Phys.

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The scattering of thermal phonons (T = 2.3-3.8 K) in ZnO single crystals and related 97.5ZnO + 0.5Bi 2 O 3 + 0.5Co 3 O 4 + 0.5MnO 2 + 1Sb 2 O 3 (mol %) ceramics has been studied. It is established that the transport characteristics of phonons with thermal frequencies in ceramics at liquid helium temperatures are determined by the presence of Co 2+ ions in ZnO grains. A model of phonon transport in ZnO based ceramics is proposed that takes into account the electron states of cobalt. The energy of the corresponding level is esti mated at Δ ≈ 5 K. Manifestations of the ferromagnetic effect are revealed.

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Magnetic properties of Fe doped, Co doped, and Fe+Co co-doped ZnO

Cited by 70 publications

References 26 publications

Effect of Calcination on Structural and Magnetic Properties of Co-Doped ZnO Nanostructures

Effect of Calcination on Structural and Magnetic Properties of Co-Doped ZnO Nanostructures

Effects of Annealing Temperature and Dopant Concentration on the Structural, Optical, and Magnetic Properties of Iron-Doped ZnO Samples

Specific features of thermal phonon scattering and ferromagnetic properties of ZnO varistor ceramics

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