Magnetic resonance in superparamagnetic zinc ferrite

Singh, Jitendra Pal; Dixit, Gagan; Srivastava, R.C.; Kumar, Hemant; Agrawal, H.M.; Chand, Prem

doi:10.1007/s12034-013-0528-2

Cited by 10 publications

(5 citation statements)

References 27 publications

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“…60 The first derivative of the X-band EPR spectrum of the CF5 sample is shown in Figure 11. The small values of ΔH pp in low temperature region showed negligible dipolar interactions among the small sized nanoparticles (7 nm) 10,61 as seen in Figure 9. This dissimilar behavior of the CF5 sample at low temperature compared to CF2, CF3, and CF6 was related to the magnetic crystalline anisotropy combined with the random orientations of the particles.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

et al. 2015

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A series of CoFe 2 O 4 nanoparticles were formed through a variant hydrothermal synthesis based in a self-assembly oil-water system in autoclaves at 200 °C in the presence of octadecylamine and the trivalent iron and cobalt acetylacetonates. The variation of the water content, the different valence of cobalt precursor (Co(II) and Co(III)) as well as Fe:Co precursor ratios (2:1 and 1:1) were studied. CoFe 2 O 4 nanoparticles with a size range 9-16 nm of high crystallinity and enhanced saturation magnetization (~89 emu g -1 ) have been isolated and characterized. Raman spectroscopy provided information concerning the lattice strain, while incorporation of Co 2+ at T d sites of the spinel indicated a different inversion degree (0.67-0.60) among the samples. EPR studies showed that EPR signal and spin relaxation process were size dependent and influenced by aggregation effects.CoFe 2 O 4 nanoparticles were converted to dual agents via a reaction between the free amine groups of the organic coating and the sulfonyl group of the fluorescent dye sulforhodamine B acid chloride (SRB) and NMR relaxometric properties were measured.The relatively high transverse relaxivity values, r 2 (232.0-130.3 mM -1 s -1 ) were attributed to nanocluster effects in aqueous suspensions in respect with the amount of SRB and encourage their potential application as versatile agents in theranostics.

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Section: ■ Results and Discussionmentioning

confidence: 92%

Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

et al. 2015

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“…The broadness of 8 FMR signal in any ferrite material can be caused by dipolar-dipolar interaction among magnetic particles and superexchange interactions between Fe metal ions via nonmagnetic O ion (Fe-O-Fe) [39]. As is well known, dominant dipole-dipole interaction gives rise to broad linewidth, although dominant superexchange interactions cause narrow linewidth at the FMR signal shape [40][41][42]. The broad absorption peak observed in Fig.…”

Section: Fmr Analysismentioning

confidence: 84%

Magnetic and Microwave Absorption Properties of Barium Hexaferrites synthesized by sol-gel method with addition of PMMA in various ratios

Gökçe

2024

Preprint

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The M-type barium hexaferrite (\(\text{B}\text{a}{\text{F}\text{e}}_{12}{\text{O}}_{19}\)) nanoparticles were synthesized by polymethylmethacrylate (PMMA) assisted sol-gel process. PMMA was used as a template at \(\text{P}\text{M}\text{M}\text{A}/\text{B}\text{a}{\text{F}\text{e}}_{12}{\text{O}}_{19}\) weight ratio of 20/80, 40/60, 60/40% in the synthesis. The X-Ray Diffraction (XRD) and scanning electron microscopy (SEM) have been used to determine the structural, compositional and morphological features of particles. DC magnetic properties have been measured by using electron spin resonance (ESR) spectrometer and vibrating sample magnetometry (VSM) at room temperature. The dielectric, magnetic and microwave properties were studied by reflection/transmission technique in the coaxial waveguide at the frequency range of 2–18 GHz. The results show that the nanorod nanoparticles are ~ 200 nm in length and ~ 40–50 nm in width for the sample with \(\text{P}\text{M}\text{M}\text{A}/\text{B}\text{a}{\text{F}\text{e}}_{12}{\text{O}}_{19}\) weight ratio of 20/80. The minimum reflection loss value of rod-shaped nanoparticles achieves ~ -50 dB with bandwidth of 2.25 GHz at -20 dB.

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“…In ferrites, Fe 3+ ions are the main responsible for EPR spectra as EPR signal for Fe 2+ ions can be only observed at very low temperature ( ∼ 4 K) because of their very short spin-lattice relaxation time [48]. On the other hand, the two main sources which are responsible for the EPR signal linewidth for any ferrite material are the interaction between magnetic dipoles among particles and the super-exchange interactions between magnetic ions through the ions of oxygen [49].…”

Section: Resultsmentioning

confidence: 99%

Structural, Magnetic Properties and Electron Paramagnetic Resonance for BaFe_12-xHg_xO₁₉Hexaferrite Nanoparticles Prepared by Co-Precipitation Method

Barakat

Bakeer

Sakr

2020

Journal of Taibah University for Science

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Barium hexaferrite nanoparticles are synthesized through co-precipitation technique at different annealing temperature. Series of BaFe 12−x Hg x O 19 nanoparticles, 0.00 ≤ x ≤ 0.30, are prepared under the best verified conditions (annealed at 1000°C) to investigate the effect of partial substitution of Hg 2+ ions on the physical properties of BaFe 12 O 19 nanoparticles. The hysteresis loops at room temperature show the behavior of hard ferromagnetic. The estimated values of saturation magnetization M s , remnant magnetization M r and magnetic moment m B rise as Hg 2+ ions content increases till x = 0.10, beyond which they reduce. A reverse trend is obtained for intrinsic coercivity Hi and coercivity Hc versus Hg 2+ ions content. BaFe 12−x Hg x O 19 nanoparticles are investigated through the measurements of electron paramagnetic resonance (EPR). The calculated EPR parameters show an enhancement for BaFe 12−x Hg x O 19 nanoparticles up to x = 0.10. The obtained results reveal that samples under investigation can be suitable candidate for different industrial applications.

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Magnetic resonance in superparamagnetic zinc ferrite

Cited by 10 publications

References 27 publications

Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Magnetic and Microwave Absorption Properties of Barium Hexaferrites synthesized by sol-gel method with addition of PMMA in various ratios

Structural, Magnetic Properties and Electron Paramagnetic Resonance for BaFe_12-xHg_xO₁₉Hexaferrite Nanoparticles Prepared by Co-Precipitation Method

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Magnetic resonance in superparamagnetic zinc ferrite

Cited by 10 publications

References 27 publications

Unveiling the Physicochemical Features of CoFe2O4 Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Unveiling the Physicochemical Features of CoFe2O4 Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Magnetic and Microwave Absorption Properties of Barium Hexaferrites synthesized by sol-gel method with addition of PMMA in various ratios

Structural, Magnetic Properties and Electron Paramagnetic Resonance for BaFe12-xHgxO19Hexaferrite Nanoparticles Prepared by Co-Precipitation Method

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Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Unveiling the Physicochemical Features of CoFe₂O₄ Nanoparticles Synthesized via a Variant Hydrothermal Method: NMR Relaxometric Properties

Structural, Magnetic Properties and Electron Paramagnetic Resonance for BaFe_12-xHg_xO₁₉Hexaferrite Nanoparticles Prepared by Co-Precipitation Method