Influence of gadolinium (Gd3+) ion substitution on structural, magnetic and electrical properties of cobalt ferrites

Kadam, A. B.; Mande, Vishwanath K.; Kadam, S. B.; Kadam, R.H.; Shirsath, Sagar E.; Borade, Rameshwar B.

doi:10.1016/j.jallcom.2020.155669

Cited by 78 publications

(11 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…figure that the experimental values have been found to decrease by increasing the zinc concentration. The cations distribution and electron exchange between Fe 2+ -Fe 3+ ions within the spinel lattice (octahedral site) plays an important role in the electrical values of ferrites, and there are plenty of articles discussing this aspect, trying to explain the observable stoichiometry dependence[34,35]. Shown in Fig.7is the change in dielectric loss (tan δ) as a function of temperature at various frequencies.…”

mentioning

confidence: 99%

WITHDRAWN: Zinc Substituted Nickel-cobalt Nano-ferrites via Citrate-gel Auto-combustion Method for High-frequency Applications: Studies on Crystal Structure and Dielectric Properties

Oumezzine

Iuga

Enculescu

et al. 2021

Preprint

View full text Add to dashboard Cite

Ni0.8−xZnxCo0.2Fe2O4 (x = 0.0, 0.05, 0.10 and 0.20) were prepared by citrate-gel auto-combustion method. The structural investigation using powder X-ray diffraction (XRD) showed the formation of single-phase cubic spinel structures with Fd-3m space group for all prepared samples. As the Zn2+ concentration is increased, the values of the lattice constant, tetrahedral and octahedral bond lengths undergo significant change. The absolute experimental lattice parameters are closely to the Vegard’ s law derived ones, suggesting that the cations concentration fairly correspond with those calculated prior chemical synthesis. Fourier transform infrared (FTIR) absorption bands at 594–400 cm− 1 confirm the formation of spinel structure. The values of dielectric constant and loss tangent were reported to decline with frequency and the Zn2+composition (x). Incorporation of Zn at nickel-cobalt resulted in decrease in ac conductivity at RT. Here, we report a low loss tangent factor of the order of 8 × 103for the sample with x = 0.20 make this composition suitable for high frequency applications. Imaginary electric modulus studies unveil the presence of non-Debye type of dielectric relaxation phenomenon. The activation energy of our samples calculated from modulus spectra is found to increase with further substitution of Zn2+ concentration.

show abstract

mentioning

confidence: 99%

WITHDRAWN: Zinc Substituted Nickel-cobalt Nano-ferrites via Citrate-gel Auto-combustion Method for High-frequency Applications: Studies on Crystal Structure and Dielectric Properties

Oumezzine

Iuga

Enculescu

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Therefore, the doping of Gd 3+ ions on the B site reduces the magnetization of octahedral sublattices. Hence, net magnetization decreases on increasing Gd 3+ concentration further, and hence the saturation magnetization reduces with a surge in Gd 3+ content, as shown in figure 7 and Table II (Kadam et al, 2020;Sahanashree et al, 2018;George et al, 2020). It is also clearly reflected in Table II that as Gd 3+ content rises, coercivity (H c ) and remanence magnetization (M r ) values also decrease.…”

Section: Table II Magnetic Parameters Formentioning

confidence: 81%

Reitveld refinement, structural, optical band gap and low-temperature magnetic characterization of Gd3+ doped spinel cubic CoFe2O4 nanoparticles

Kumar

Gora

Kumar

et al. 2022

Bangladesh J. Sci. Ind. Res.

View full text Add to dashboard Cite

The current study unravels the structural, optical band gap and magnetic characteristics of rare-earth (RE) gadolinium (Gd) substituted CoGdxFe2-xO4 (x= 0.00 - 0.10, in the interval of 0.02) nanocrystallites synthesized by the sol-gel self-ignition route. The XRD analysis and Rietveld refinement confirmed the existence of a single cubic phase with a crystallite size of ~15-21 nm range, further confirmed by HRTEM results. SEM images confirmed the well-known nano-size morphology for all the samples. The magnetization measurements show a hard ferromagnetic nature for all specimens within the temperature range of 20-300K. Coercivity, remanent, and saturation magnetization monotonically increased with a reduction in temperature from 300K to 20K. UV-Vis absorbance results show that the band gap energy of CoFe2O4 nanoparticles (NPs) decreases with increasing Gd3+ ion doping and have band gap energy values of 2.47, 2.15, 2,02, 2.00, 1.43 and 1.95 eV for x= 0.00, 0.02, 0.04, 0.06, 0.08, 0.10, respectively in CoGdxFe2-xO4 nanoferrites. The present study reveals that structural, optical band gap and magnetic properties could be altered by monitoring the quantity of gadolinium in cobalt nanoferrites. Bangladesh J. Sci. Ind. Res. 57(3), 173-186, 2022

show abstract

“…These lattice changes along with size confinement result in intrinsic strain within the NPs, which has direct implications on the inherently existing oxygen vacancy defects, point defects, grain boundary imperfections, stacking faults, and dislocation. The intrinsic strain of the NPs can be calculated by the Williamson–Hall (W–H) plot using the strain-induced broadening of XRD peaks after correcting the instrumental broadening by the Scherrer formula . From the slope of the linear fitting of W–H plots, the crystallographic strains obtained for C-P, C-1, C-2, and C-3 are 3.59 × 10 –5 , 1.24 × 10 –3 , 1.40 × 10 –3 , and 1.46 × 10 –3 , respectively (Figure S3).…”

Section: Resultsmentioning

confidence: 99%

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

2020

View full text Add to dashboard Cite

Spinel ferrites, especially cobalt ferrite, have the capability of preserving sufficient magnetization (M s) and coercive field (H c). However, precise nanostructuring is needed to sustain the steady ferrimagnetic (FiM) response with high H c and remnant magnetization (M r). By a two-step process involving co-precipitation and inert calcination, CoFe2O4 nanoparticles (NPs) with inherent lattice strain were achieved with appreciable magnetic anisotropy. The disordered spins on the NP surface are found to be the key for maintaining the anisotropy and squareness (M r/M s) of hysteresis loops, the extent of which is a function of the processing temperature and NP size. The freezing of surface spins results in 2.8 and 1.2 nm thick spin glass (SG) layers for the as-prepared and 350 °C-calcined CoFe2O4 NPs, respectively, analyzed at 5 K. The frozen surface spins pin the core FiM spins, resulting in the exchange bias (H eb) coupling. At room temperature, 20 nm NPs exhibit permanent magnet-like features with a maximum energy product, BHmax, of 2.4 MGOe, which is quite promising considering CoFe2O4 as an environmentally friendly alternative to the hazardous rare-earth-based permanent magnets. Our CoF2O4 NP ensemble delivers both intriguing low-temperature magnetic properties having academic and technological interests and worthwhile room-temperature features that have direct translational relevance.

show abstract

Influence of gadolinium (Gd3+) ion substitution on structural, magnetic and electrical properties of cobalt ferrites

Cited by 78 publications

References 56 publications

WITHDRAWN: Zinc Substituted Nickel-cobalt Nano-ferrites via Citrate-gel Auto-combustion Method for High-frequency Applications: Studies on Crystal Structure and Dielectric Properties

WITHDRAWN: Zinc Substituted Nickel-cobalt Nano-ferrites via Citrate-gel Auto-combustion Method for High-frequency Applications: Studies on Crystal Structure and Dielectric Properties

Reitveld refinement, structural, optical band gap and low-temperature magnetic characterization of Gd3+ doped spinel cubic CoFe2O4 nanoparticles

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

Contact Info

Product

Resources

About