Correlation between microstructure, cation distribution and magnetism in Ni1−xZnxFe2O4nanocrystallites

Hölscher, Jennifer; Andersen, Henrik L.; Saura-Múzquiz, Matilde; Garbus, Pelle Gorm; Christensen, Mogens

doi:10.1039/c9ce01324e

Cited by 18 publications

(17 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[5,[22][23][24][25][26][27][28][29] This is mainly related to the redistribution of cations in the lattice, which occurs when grain sizes are decreased to nanoscale. [24,[30][31][32] In contrast to bulk ZF (of normal spinel structure), nanoparticles of stoichiometric zinc ferrite (ZF NPs) reveal a mixed spinel structure, where Zn 2+ and Fe 3+ cations are distributed between () Td and [] Oh sites. Non-stoichiometry of nanoparticles is usually compensated for by point defects in the crystal structure.…”

Section: Introductionmentioning

confidence: 99%

“…[22,33] This is why in case of ZN NPs even a small deviation of Zn content from the stoichiometric composition causes significant changes of physical-chemical properties, especially magnetic [33][34][35][36][37] and structural. [22,23,31,36,38] ANGELIKA KMITA Several doping models of Fe 3 O 4 nanoparticles by zinc ions Zn 2+ leading to the formation of non-stoichiometric zinc ferrite (NZF), Zn x Fe 3Àx O 4 are proposed in the literature. [23,24,34,35,[39][40][41][42] Ma et al [34] discuss two models of doping that are dependent on the concentration of Zn 2+ ions in NZF NPs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Thermal Treatment at Inert Atmosphere on Structural and Magnetic Properties of Non-stoichiometric Zinc Ferrite Nanoparticles

Kmita

Żukrowski

Kuciakowski

et al. 2021

Metall Mater Trans A

View full text Add to dashboard Cite

Zinc ferrite nanoparticles were obtained by chemical methods (co-precipitation and thermal decomposition of metalorganic compounds) and systematically probed with volume (XRD, VSM), microscopic (TEM) and element sensitive probes (ICP-OES, Mössbauer Spectroscopy, XPS, XAFS). Magnetic studies proved the paramagnetic response of stoichiometric ZnFe2O4 (ZF) nanoparticles, while superparamagnetic behavior was observed in as-synthesized, non-stoichiometric ZnxFe3−xO (NZF) nanoparticles. Upon annealing up to 1400 °C in an inert atmosphere, a significant change in the saturation magnetization of NZF nanoparticles was observed, which rose from approximately 50 up to 140 emu/g. We attribute this effect to the redistribution of cations in the spinel lattice and reduction of Fe3+ to Fe2+ during high-temperature treatment. Iron reduction is observed in both ZF and NZF nanoparticles, and it is related to the decomposition of zinc ferrite and associated sublimation of zinc oxide.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Thermal Treatment at Inert Atmosphere on Structural and Magnetic Properties of Non-stoichiometric Zinc Ferrite Nanoparticles

Kmita

Żukrowski

Kuciakowski

et al. 2021

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…9 However, such increase in saturation is only achievable up to a certain substitution degree, above which the aforementioned super-exchange interactions are disrupted by the non-magnetic cation, causing an antiferromagnetic coupling between the octahedral sites. [10][11][12][13] (M s ) values up to ca. 127 Am 2 kg -1 (175 Am 2 kg -1 if only the magnetic atoms are taken into account) have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…10,22,23 However, the cation distribution can differ due to synthesis strategy, heating treatment and crystallite size. 12,13,19,[23][24][25][26] Quenching MnFe 2 O 4 after annealing leads to a more inverse material, 27,28 while slow cooling of ZnFe 2 O 4 leads to the thermodynamically stable configuration with Zn solely occupying the tetrahedral sites, i.e. a normal spinel.…”

mentioning

confidence: 99%

Magnetic Property Enhancement of Spinel Mn–Zn Ferrite through Atomic Structure Control

et al. 2020

Self Cite

View full text Add to dashboard Cite

Temperature treatment of magnetic Mn-Zn ferrites with the composition Mn 0.6 Zn 0.2 Fe 2.2 O 4 up to 1100 °C results in a tremendous enhancement of the saturation magnetization by more than 60%. Employing a robust combined Rietveld refinement of powder X-ray and neutron diffraction (PXRD and NPD) data, it is revealed how a reordering of the cations takes place during the annealing step, the extent of which depends on the annealing temperature. While Zn(II) exclusively occupies tetrahedral sites throughout the whole temperature range, as the annealing temperature increases up to 700 °C, the Mn(II) cation distribution shifts from 80(7)% of the total Mn content occupying the octahedral sites (partly inverse spinel)to Mn only being present on the tetrahedral sites (normal spinel). Above 700 °C, pronounced crystallite growth is observed, followed by an increase of the saturation magnetization. Complementary techniques such as energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) confirm an even cation distribution and the particle growth with annealing temperature. The structural changes caused by annealing of spinel ferrites directly alter the magnetic properties of the materials, thus serving as an easy handle for enhancing their magnetic properties.values typically ranging between 23 and 85 Am 2 kg -1 . [15][16][17] The wide range of values in the literature can be attributed to modifications of microstructure and cation distribution. Despite these characteristics being key to explaining the differences in the magnetic performance of Mn-Zn substituted spinel ferrites, there is a general lack of investigations addressing the microstructure and cation distribution. This is partly because the cation distribution effect is particularly difficult to unravel in the case of neighboring atoms in the periodic table when using laboratory X-rays or a standard synchrotron experiment. Even though powder Xray diffraction (PXRD) allows modeling the site occupancies of all cations in the crystallographic structure, the reliability of a model is compromised when elements are in the vicinity of each other in the periodic table. This is a challenge in complex spinel ferrites, as the transition metals have a similar number of electrons and therefore similar atomic form factors, e.g. Mn (Z = 25) and Fe (Z = 26). A way to circumvent this is to collect neutron powder diffraction (NPD) data. When using NPD, strong contrasts between cations can be achievable, as the scattering lengths vary erratically with atomic number, e.g. Mn (b Mn = -3.73 fm) and Fe (b Fe = 9.45 fm). This facilitates modeling the cation distribution in spinel ferrites reliably.The cation distribution of a sample depends on the crystal field stabilization energies of the individual cations, their charge and their ionic radius. 18 Annealing can introduce changes in the cation distribution.However, not only the heating step is decisive in modifying the cation distribution, but also the cooling procedure is crucial in controlling it and ther...

show abstract

“…1533163), which is 8.3806 Å. The slow increase in the lattice constant with the increase in calcination temperature could be related to the variation in microstructure during thermal treatment, as well as to the ordering or reordering of cations in the cubic spinel structure [ 34 ], which has been confirmed by XPS data.…”

Section: Resultsmentioning

confidence: 90%

Synthesis and Characterization of New Ferrite-Lignin Hybrids

Spiridon¹,

Dascalu²,

Coroabă³

et al. 2021

Polymers

View full text Add to dashboard Cite

The paper presents the synthesis and characterization of new cobalt ferrite-lignin hybrids. The hybrids were obtained through the combustion of cobalt nitrate and ferric nitrate, two kinds of lignin being used as combustion agents. The temperatures of calcination were 500 °C and 900 °C, respectively. The hybrids were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The magnetic properties were also assessed by vibrating sample magnetometer system (VSM). This facile synthesis method made it possible to obtain cobalt ferrite-lignin hybrids with a spinel structure. Their particle sizes and crystallite sizes have increased with an increment in the calcination temperature. A different occupancy of cations at octahedral and tetrahedral sites also occurred upon the increase in temperature. The hybrids comprising organic lignin presented the best magnetic properties.

show abstract

Correlation between microstructure, cation distribution and magnetism in Ni_1−xZn_xFe₂O₄nanocrystallites

Abstract: A reliable crystallographic model of Ni1−xZnxFe2O4 is presented using a combination of different methods; TEM, STEM-HAADF, and powder diffraction data from different sources (in-house, synchrotron and neutron).

Cited by 18 publications

References 38 publications

Effect of Thermal Treatment at Inert Atmosphere on Structural and Magnetic Properties of Non-stoichiometric Zinc Ferrite Nanoparticles

Effect of Thermal Treatment at Inert Atmosphere on Structural and Magnetic Properties of Non-stoichiometric Zinc Ferrite Nanoparticles

Magnetic Property Enhancement of Spinel Mn–Zn Ferrite through Atomic Structure Control

Synthesis and Characterization of New Ferrite-Lignin Hybrids

Contact Info

Product

Resources

About