Room temperature ferromagnetism in vacuum annealed ZnFe2O4 nanoparticles

Saravanakumar, A.; Raja, S.; Venkateswaran, C.; Philip, John; Raj, Baldev

doi:10.1063/1.3374332

Cited by 87 publications

(44 citation statements)

References 23 publications

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“…This will change the room‐temperature magnetic behavior of ZnFe 2 O 4 from antiferromagnetic to ferrimagnetic. The ferrimagnetic properties of ZnFe 2 O 4 are also possible to obtain through formation of oxygen vacancies in the structure and surface strain , as well as by decreasing the amorphous phase content or particle size . Another way of introducing ferrimagnetic properties to zinc ferrite is by doping it with other metal ions .…”

Section: Introductionmentioning

confidence: 99%

Effect of antisite defects on the magnetic properties of ZnFe₂ O₄

Šutka

Pärna

Zamovskis

et al. 2013

Phys. Status Solidi A

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Magnetic zinc ferrite (ZnFe2O4) nanopowders were synthesized using the sol–gel autocombustion method. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) measurements demonstrated that thermal decomposition of the 1‐mm‐thick xerogel layers in air formed monophasic spinel ferrite nanopowders with a particle size less than 30 nm. X‐ray photoelectron spectroscopy (XPS) showed that the obtained reaction product contained antisite defects, with zinc ions occurring at the octahedral sites of the spinel structure. The concentration of antisite defects or inversion degree decreased when the relatively low annealing temperature was increased from 150 to 500 °C. Overall, the obtained ZnFe2O4, which is usually antiferromagnetic (exhibits no magnetic moment), demonstrated high saturation magnetization (60.7 emu g−1), and coercive force (56 Oe). This was due to the presence of the antisite defects in the structure.

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Section: Introductionmentioning

confidence: 99%

Effect of antisite defects on the magnetic properties of ZnFe₂ O₄

Šutka

Pärna

Zamovskis

et al. 2013

Phys. Status Solidi A

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“…in tetrahedral sites and Fe 3? in octahedral sites with antiparallel arrangement of magnetic moments [34]. However, the ZnFe 1.97 Eu 0.03 O 4 NPs exhibit the weak ferromagnetic behavior.…”

Section: Resultsmentioning

confidence: 96%

Effects of annealing temperature on the magnetic properties of ZnFe1.97Eu0.03O4 nanoparticles

Yang

Han

Liu

et al. 2015

J Mater Sci: Mater Electron

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The ZnFe 1.97 Eu 0.03 O 4 nanoparticles were prepared with sol-gel method. The effects of sintering temperature on the structural, morphological and magnetic properties were investigated in detail. The results revealed that the ZnFe 1.97 Eu 0.03 O 4 NPs exhibited weak ferromagnetic properties due to the formation of defects in ZnFe 2 O 4 caused by Eu 3? doping. Moreover, the increased sintering temperature not only enlarged the grain size but also decreased the magnetization of ZnFe 1.97 Eu 0.03 O 4 NPs due to the decrease of defects in the crystal lattices.

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“…3b, ZnFe 2 O 4 /mCNTs is found have a remanence of 0.104 emu/g and coercivity 70 Oe. The magnetization curve of ZnFe 2 O 4 nanoparticles prepared by co-precipitation method shows super-paramagnetic behavior [20]. CNTs decorated with ZnFe 2 O 4 nanoparticles [21] show an incremental value of magnetization compared to pure ZnFe 2 O 4 nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

Composition, Electronic and Magnetic Investigation of the Encapsulated ZnFe2O4 Nanoparticles in Multiwall Carbon Nanotubes Containing Ni Residuals

et al. 2015

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We report investigation on properties of multiwall carbon nanotubes (mCNTs) containing Ni residuals before and after encapsulation of zinc ferrite nanoparticles. The pristine tubes exhibit metallic character with a 0.3 eV reduction in the work function along with ferromagnetic behavior which is attributed to the Ni residuals incorporated during the preparation of tubes. Upon encapsulation of zinc ferrite nanoparticles, 0.5 eV shift in Fermi level position and a reduction in both the π band density of state along with a change in the hybridized sp2/sp3 ratio of the tubes from 2.04 to 1.39 are observed. As a result of the encapsulation, enhancement in the σ bands density of state and coating of the zinc ferrite nanoparticles by the internal layers of the CNTs in the direction along the tube axis is observed. Furthermore, Ni impurities inside the tubes are attracted to the encapsulated zinc ferrite nanoparticles, suggesting the possibility of using these particles as purifying agents for CNTs upon being synthesized using magnetic catalyst particles. Charge transfer from Ni/mCNTs to the ZnFe2O4 nanoparticles is evident via reduction of the density of states near the Fermi level and a 0.3 eV shift in the binding energy of C 1 s core level ionization. Furthermore, it is demonstrated that encapsulated zinc ferrite nanoparticles in mCNTs resulted in two interacting sub-systems featured by distinct blocking temperatures and enhanced magnetic properties; i.e., large coercivity of 501 Oe and saturation magnetization of 2.5 emu/g at 4 K.

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Room temperature ferromagnetism in vacuum annealed ZnFe2O4 nanoparticles

Cited by 87 publications

References 23 publications

Effect of antisite defects on the magnetic properties of ZnFe₂ O₄

Effect of antisite defects on the magnetic properties of ZnFe₂ O₄

Effects of annealing temperature on the magnetic properties of ZnFe1.97Eu0.03O4 nanoparticles

Composition, Electronic and Magnetic Investigation of the Encapsulated ZnFe2O4 Nanoparticles in Multiwall Carbon Nanotubes Containing Ni Residuals

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Room temperature ferromagnetism in vacuum annealed ZnFe2O4 nanoparticles

Cited by 87 publications

References 23 publications

Effect of antisite defects on the magnetic properties of ZnFe2 O4

Effect of antisite defects on the magnetic properties of ZnFe2 O4

Effects of annealing temperature on the magnetic properties of ZnFe1.97Eu0.03O4 nanoparticles

Composition, Electronic and Magnetic Investigation of the Encapsulated ZnFe2O4 Nanoparticles in Multiwall Carbon Nanotubes Containing Ni Residuals

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Effect of antisite defects on the magnetic properties of ZnFe₂ O₄

Effect of antisite defects on the magnetic properties of ZnFe₂ O₄