Magnetic resonance study of Ce and Gd doped NiFe2O4 nanoparticles

Dixit, Gagan; Singh, Jitendra Pal; Srivastava, R.C.; Agrawal, H.M.

doi:10.1016/j.jmmm.2011.08.027

Cited by 128 publications

(58 citation statements)

References 25 publications

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“…Due to the dependence of ε on R, its variation reflects the thermal expansion coefficient of the samples when they were annealed, which is assigned to the change of spacing within and/or between the nanoparticles. The increase of ε proves growth of the crystal lattice as T increases [11,26,27].…”

Section: Resultsmentioning

confidence: 94%

“…It is displayed that S increases to a maximum value at 600 C and decreases thereafter, whereas ε has opposite behavior. This can be explained as dependence of S on both R and D x , where S is inversely proportional to R [26]. The negative values of ε reveals compressive strain [26,27].…”

Section: Resultsmentioning

confidence: 99%

“…This can be explained as dependence of S on both R and D x , where S is inversely proportional to R [26]. The negative values of ε reveals compressive strain [26,27]. Due to the dependence of ε on R, its variation reflects the thermal expansion coefficient of the samples when they were annealed, which is assigned to the change of spacing within and/or between the nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

“…The hysteresis loops for T ¼ 700 and 900 C show a sharp decrease in the saturation magnetization (M s ) and increase in the coercivity (H c ) which explains the phase transformation from cubic spinel to Z-type hexagonal structure. Thus, the samples annealed at 700 and 900 C may consider hard magnetic materials [1,2,26], which proves the transformation of these nanoferrites from soft to hard magnetic nature. Variation of M s and H c with T is seen in Fig.…”

Section: The Magnetic Hysteresis Loopsmentioning

confidence: 99%

“…Fig. 15 [15,18,19,26]. Increasing R leads to colinearity or decrease of the canting of spins on the nanoparticle surface which causes increase in magnetization at the crystal sublattices i.e.…”

Section: M€ Ossbauer Spectramentioning

confidence: 99%

See 4 more Smart Citations

Annealing effect on structural phase transition of as-synthesized Mg0.1Sr0.1Mn0.8Fe2O4 nanoparticles

Amer

Meaz

Attalah³

et al. 2016

Journal of Alloys and Compounds

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: The Magnetic Hysteresis Loopsmentioning

confidence: 99%

Section: M€ Ossbauer Spectramentioning

confidence: 99%

See 3 more Smart Citations

Annealing effect on structural phase transition of as-synthesized Mg0.1Sr0.1Mn0.8Fe2O4 nanoparticles

Amer

Meaz

Attalah³

et al. 2016

Journal of Alloys and Compounds

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Influence of Dysprosium Doping on Structural, Magnetic, and Optical Properties of Ni–Zn Ferrites

Ganesh

Sandeep

Chanti

et al. 2023

Physica Status Solidi (a)

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The spinel ferrites with the compositional formula Ni0.8Zn0.2Fe2−xDyxO4 (x = 0, 0.004, 0.008, 0.012, 0.016) have been prepared using the sol–gel method. The X‐ray diffraction measurements confirm the cubic spinel structure of the sample with a space group of Fd‐3m. Morphological analysis of scanning electron microscope images reveals that the particles are spherical in shape. Energy dispersive X‐ray spectroscopy (EDX) confirms the elemental composition. Thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC) analysis of synthesized dysprosium (Dy) doped Ni–Zn ferrites are carried out from 25 to 700 °C. Fourier‐transform infrared (FTIR) spectroscopy studies reveal the stretching and bending vibrations of the various bonds presented in the compounds. The UV–vis absorption spectrum indicates the energy gap values which small decrease with the Dy concentration increase. Raman spectroscopy reveals the crystal distortion and phases of the samples. The room temperature magnetic measurements (M–H loops) are carried out to study the effect of Dy doping on magnetic properties.

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Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation

Xiao

Zhang

et al. 2022

Small

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the sluggish kinetics of oxygen evolution reaction (OER) for water splitting still hinders the wide application of this technology. Ru-and Ir-based oxides are highly active catalysts for OER, nevertheless, the scarcity and cost of Ru and Ir largely constrains the broad deployment of hydrogen production utilities. [4][5][6] To this end, transition metal oxide (TMO) electrocatalysts have been extensively investigated due to their earth-abundant and outstanding OER performance. [7][8][9][10] It is remarkable that spinel oxides present stunning catalytic performance for OER in alkaline electrolytes, benefitting from the coexistence of tetrahedral (T d ) and octahedral (O h ) transition-metal cation sites in TMOs, whereas such a complex structure with multiple sites also brings a great challenge on precise identification toward active sites for OER. [11][12][13][14] The tailoring of catalytic active sites for spinel oxides is of importance on the design of highly efficient electrocatalysts for OER, but the active sites of spinel oxides for OER are still elusive. [11,[15][16][17][18] For example, it is reported that the high OER activity of ZnCo 2 O 4 relies on the amounts of Co 3+ on the O h sites. [19] However, on the contrary, it also has been found that the Zn 2+ at T d sites is contributed Magnetic field enhanced electrocatalysis has recently emerged as a promising strategy for the development of a viable and sustainable hydrogen economy via water oxidation. Generally, the effects of magnetic field enhanced electrocatalysis are complex including magnetothermal, magnetohydrodynamic and spin selectivity effects. However, the exploration of magnetic field effect on the structure regulation of electrocatalyst is still unclear whereas is also essential for underpinning the mechanism of magnetic enhancement on the electrocatalytic oxygen evolution reaction (OER) process. Here, it is identified that in a mixed NiFe 2 O 4 (NFO), a large magnetic field can force the Ni 2+ cations to migrate from the octahedral (O h ) sites to tetrahedral (T d ) sites. As a result, the magnetized NFO electrocatalyst (NFO-M) shows a two-fold higher current density than that of the pristine NFO in alkaline electrolytes. The OER enhancement of NFO is also observed at 1 T (NFO@1T) under an operando magnetic field. Our first-principles calculations further confirm the mechanism of magnetic field driven structure regulation and resultant OER enhancement. These findings provide a strategy of manipulating tetrahedral units of spinel oxides by a magnetic field on boosting OER performance.

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Magnetic resonance study of Ce and Gd doped NiFe2O4 nanoparticles

Cited by 128 publications

References 25 publications

Annealing effect on structural phase transition of as-synthesized Mg0.1Sr0.1Mn0.8Fe2O4 nanoparticles

Annealing effect on structural phase transition of as-synthesized Mg0.1Sr0.1Mn0.8Fe2O4 nanoparticles

Influence of Dysprosium Doping on Structural, Magnetic, and Optical Properties of Ni–Zn Ferrites

Magnetic Field Manipulation of Tetrahedral Units in Spinel Oxides for Boosting Water Oxidation

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