Synthesis and magnetic behaviour of Mn:ZnO nanocrystalline powders

Sagar, Raghavendra; Buddhudu, S.

doi:10.1016/j.saa.2009.12.014

Cited by 30 publications

(14 citation statements)

References 36 publications

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“…A similar decrease in the crystal lattice parameters of ZnO NC in comparison with single-crystal ZnO was observed in works [4,5]. As a rule, doping of ZnO NC with Mn impurity leads to an increase in the unit cell volume V [6]. Therefore, the answer to the question why this does not happen in our case requires additional research.…”

Section: Resultssupporting

confidence: 77%

“…(5) Acetone is obtained during this decomposition. Its decomposition leads to the appearance of hydrogen CH3COCH3 → C2H4 + H2↑ + CО↑ (6) During long-term heat treatment of samples, due to the recrystallization of samples and their additional oxidation, the concentration of defects in the NC decreases, so it is possible to register only HFS Mn 2+ ions in the EPR spectra. EPR spectra of various defects are observed in zinc oxide.…”

Section: Resultsmentioning

confidence: 99%

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Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Коваленко¹,

Vorovsky²,

Хмеленко³

et al. 2020

JPhysElectron

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In the work, the nanocrystals ZnO and ZnO:Mn with a concentration of Mn 2 and 4 at.% were obtained by the low-temperature freeze-drying method. For this purpose, solutions of zinc acetate Zn(CH3COO)2∙2H2O and manganese one Mn(CH3COO)2∙4H2O were used. By means of XRD, it is established that nanocrystals (NC’s) have a pure phase and wurtzite-type hexagonal lattice, their size is d ~ 65 nm. The EPR spectra of the samples have a broad absorption line. It is due to the presence of a large number of intrinsic and impurity defects in the NC’s. These defects are the result of the destructive action of hydrogen, which is a product of the thermal decomposition of zinc and manganese acetates. It is shown that there is a relationship between the number of crystal lattice defects in the ZnO:Mn NC’s and their ferromagnetic properties at room temperature. Samples of ZnO:Mn with a concentration of Mn 2 and 4 at.%. have a specific magnetization value of Мs equal to 0.089 and 0.045 emu/g, respectively. The results can have great potential in spintronic devices and spin-based electronics.

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Коваленко¹,

Vorovsky²,

Хмеленко³

et al. 2020

JPhysElectron

View full text Add to dashboard Cite

show abstract

“…The results indicate that c increases with increasing doping concentration. The increase in the lattice parameter may be due to the larger ionic radius of Mn 2+ (0.83 Å) than that of Zn 2+ in wurtzite structure (0.74 Å) [ 32 ]. However, the lattice parameter a has a slight shrink for 9 at% Mn-doped ZnO.…”

Section: Resultsmentioning

confidence: 99%

Ferromagnetic ordering in Mn-doped ZnO nanoparticles

et al. 2014

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Zn 1 -x Mn x O nanoparticles have been synthesized by hydrothermal technique. The doping concentration of Mn can reach up to 9 at% without precipitation or secondary phase, confirmed by electron spin resonance (ESR) and synchrotron X-ray diffraction (XRD). Room-temperature ferromagnetism is observed in the as-prepared nanoparticles. However, the room-temperature ferromagnetism disappears after post-annealing in either argon or air atmosphere, indicating the importance of post-treatment for nanostructured magnetic semiconductors.

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“…The area of integration curves were analogous to the number of spins that participated in the FMR. The number of spins ( N spins ) that participated in the ferromagnetic resonance was estimated by using the formula in eq , where I is the peak-to-peak height of the EPR signal (arbitrary units) and Δ H is the line width (in mT). Parts C and D of Figure clearly indicated the correspondence between the saturation magnetization ( M s ) with the area of integration curves and the number of spins that participated in the FMR, respectively.…”

Section: Resultsmentioning

confidence: 99%

XANES, EXAFS, EPR, and First-Principles Modeling on Electronic Structure and Ferromagnetism in Mn Doped SnO₂ Quantum Dots

et al. 2019

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The effect of Mn dopant on the electronic structure and magnetic properties of SnO2 quantum dots was investigated using X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS), electron paramagnetic resonance, and first-principles modeling. The results demonstrated that dilute Mn atoms substituted for Sn generates numerous oxygen vacancies. Interestingly, lower Mn doping concentration (2%) favored the formation of Mn3+ structures and increase of Mn doping to higher concentration (10% Mn) led to predominance of Mn3+ with a small fraction of Mn2+ configuration. The slight increase in bond length observed for 10% Mn doped SnO2 QDs in EXAFS also corroborates with the XANES results where the absorption edge was shifted to lower energy, giving an indication of a very small presence of Mn in the +2 oxidation state. Electron paramagnetic resonance studies revealed the exchange coupled Mn interactions and also changes in distribution of local magnetic configurations with the increased dopant level of Mn. The considerable enhancement in the spin carrier density of states (DOS) and changes in the configuration of Mn upon variation in doping concentration in SnO2 QDs demonstrate the effective role of Mn in modulating the electronic structure.

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Synthesis and magnetic behaviour of Mn:ZnO nanocrystalline powders

Cited by 30 publications

References 36 publications

Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Ferromagnetic ordering in Mn-doped ZnO nanoparticles

XANES, EXAFS, EPR, and First-Principles Modeling on Electronic Structure and Ferromagnetism in Mn Doped SnO₂ Quantum Dots

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Synthesis and magnetic behaviour of Mn:ZnO nanocrystalline powders

Cited by 30 publications

References 36 publications

Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Ferromagnetic properties of ZnO:Mn nanocrystals obtained by the freeze-drying method

Ferromagnetic ordering in Mn-doped ZnO nanoparticles

XANES, EXAFS, EPR, and First-Principles Modeling on Electronic Structure and Ferromagnetism in Mn Doped SnO2 Quantum Dots

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Product

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XANES, EXAFS, EPR, and First-Principles Modeling on Electronic Structure and Ferromagnetism in Mn Doped SnO₂ Quantum Dots