New method to calculate Mössbauer recoilless f-factors in NiFe2O4. Magnetic, morphological and structural properties

Salazar-Tamayo, H.; García, K.E.; Barrero, C. A.

doi:10.1016/j.jmmm.2018.09.066

Cited by 36 publications

(13 citation statements)

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“…A is the recoilless f-factors ratio for Fe 3+ cations at at room temperature (RT) [24] ; we found A Table 2 are outside the range of expected theoretical values. Of course, equation 4can only be used when cation disordering is present in NiFe 2 O 4 .…”

Section: Resultscontrasting

confidence: 54%

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

2019

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Nickel ferrite (NiFe 2 O 4) was synthesized by mixing stoichiometric amounts of α-Fe 2 O 3 and NiO using mechanical milling and heat treatments at high temperatures. The physical characterization of the samples was carried out using X-ray diffraction, infrared and Raman spectroscopies, Mössbauer spectrometry, magnetization measurements, scanning electron microscopy and energy dispersive X-ray spectroscopy. We found that NiFe 2 O 4 production increases from 81 to 100 wt. % with increasing temperature. Additionally, the lattice parameter and the saturation magnetization increase with increasing temperature. On the other hand, Mössbauer spectrometry showed that there is a decrease in the subspectral areas ratio for Fe 3+ cations at tetrahedral (A) and octahedral [B] sites, A A /A B , with the increase of the temperature. In the SEM micrographs it was observed that the samples consisted of particles with irregular shapes and micrometric sizes. From IR spectra, the intensity of the 411 cm-1 band (vibrations at octahedral sites) increases relative to the intensity of the 599 cm-1 band (vibrations at tetrahedral sites) with increasing temperature. From the results obtained in the magnetization curves, it was possible to confirm the synthesis of NiFe 2 O 4. As the heat treatment temperature increases, hysteresis loops with S-type geometric forms were obtained. All the results suggest that a defective spinel NiFe 2 O 4 is formed at 1000 °C, and that as the temperature increases, the defects gradually disappear. Neither cation reordering phenomena nor possible evaporation of chemical elements were the dominant effects to account for the results. The results can be explained if it is assumed that [B]-sites cation vacancies are gradually filled with cations as the temperature of the heat treatment increases.

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Section: Resultscontrasting

confidence: 54%

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

2019

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“…A 2020 publication [ 11 ] has reviewed the numerous routes to synthesize nickel ferrite. The most used routes consist of co-precipitation [ 12 , 13 ], sol-gel [ 14 , 15 , 16 , 17 ], solid-state [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] and micro-emulsion method [ 26 ]. In this study, a solid-state method is developed to synthesize uniform particles of nickel ferrite for research into its properties as a colloid.…”

Section: Introductionmentioning

confidence: 99%

Study of the Solid-State Synthesis of Nickel Ferrite (NiFe2O4) by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Raman Spectroscopy

et al. 2021

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Spinel ferrite compounds continue to receive a lot of attention due to their unique properties. Among the numerous synthesis routes existing, the solid-state method was applied for the production of nickel ferrite, by introducing the use of a quartz vial. A mixture of nickel oxide (NiO) and hematite (Fe2O3) was ground and vacuum-sealed in the vial and different thermal treatment programs were tested. The resulting particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. For temperatures, below 1000 °C, the solid-state reaction is not complete as nickel oxide (NiO) and hematite (Fe2O3) are still present. The reaction time is a decisive parameter for the morphology of the particles obtained. If, for different reaction times, the particle size distribution is always between 0.3 and 1.7 µm, a longer reaction time leads to the formation of dense, interconnected clusters of particles. Optimal parameters to synthesize a pure phase of spherical nickel ferrite were sought and found to be a reaction temperature of 1000 °C for 72 h.

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“…But in this case, observed ratios are different for all CFDO samples. From these spectra, the ratio of a number of 26 Fe atoms at the tetrahedral site and octahedral site, i.e., n(Fe) A /n[Fe] B , of the area is calculated , (see Table ). Here, n (Fe) A is the number of 26 Fe ions at the tetrahedral site, and n [Fe] B is the number of 26 Fe ions at octahedral sites.…”

Section: Resultsmentioning

confidence: 99%

Correlation between Cation Distribution and Magnetic and Dielectric Properties of Dy³⁺-Substituted Fe-Rich Cobalt Ferrite

et al. 2022

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Designing electromagnetic materials, particularly those based on transition-metal-containing spinel ferrites, with a controlled structure, phase, and chemistry at the nanoscale dimensions while realizing enhanced electrical and magnetic properties continues to be a challenging problem. Herein, we report on the synthesis and structure− property correlation of dysprosium (Dy)-substituted iron-rich cobalt ferrite (Co 0.8 Fe 2.2−x Dy x O 4 ; CFDO; x = 0.000−0.100) oxides with variable Dy 3+ concentration. Chemical bonding analyses of CFDO nanomaterials using Raman spectroscopic analyses supported the spinel phase formation with high quality. Cation distribution determined from Mossbauer spectroscopy reveals the fact that Dy 3+ occupies the octahedral site of the spinel lattice. Saturation magnetization (M s ) values calculated using Neel's two-sublattice model and cation distribution derived from Mossbauer's studies correlate well with the magnetization values obtained from SQUID measurements. The B-site hyperfine field decreases from 52.24 ± 0.10 to 49.26 ± 0.00 T, as evidenced by the Mossbauer spectra, with Dy substitution, which decreases the Fe-ion occupancy from the octahedral site of CFDO. Frequency-dependent dielectric constant indicates electron hopping in the grain interior, which ceases above 6.3 kHz. Dielectric measurements indicate that these CFDO compounds are useful for absorption at higher frequencies. Thus, using the combined approach based on Raman and Mossbauer spectroscopic analyses, the present work elucidates the structure, chemical bonding, and magnetic properties of Dy-substituted Ferich cobalt ferrite. CFDO may serve as a model system to apply to a class of Fe-rich ferromagnetic nanomaterials for electromagnetic and sensor applications.

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New method to calculate Mössbauer recoilless f-factors in NiFe2O4. Magnetic, morphological and structural properties

Cited by 36 publications

References 36 publications

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

Study of the Solid-State Synthesis of Nickel Ferrite (NiFe2O4) by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Raman Spectroscopy

Correlation between Cation Distribution and Magnetic and Dielectric Properties of Dy³⁺-Substituted Fe-Rich Cobalt Ferrite

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New method to calculate Mössbauer recoilless f-factors in NiFe2O4. Magnetic, morphological and structural properties

Cited by 36 publications

References 36 publications

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization

Study of the Solid-State Synthesis of Nickel Ferrite (NiFe2O4) by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Raman Spectroscopy

Correlation between Cation Distribution and Magnetic and Dielectric Properties of Dy3+-Substituted Fe-Rich Cobalt Ferrite

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Correlation between Cation Distribution and Magnetic and Dielectric Properties of Dy³⁺-Substituted Fe-Rich Cobalt Ferrite