Perpendicular magnetic anisotropy in 70nm CoFe2O4 thin films fabricated on SiO2/Si(100) by the sol–gel method

Wang, X.W.; Zhang, Y.Q.; Meng, Hao; Wang, Z.J.; Zhang, Z.D.

doi:10.1016/j.jallcom.2011.05.021

Cited by 31 publications

(18 citation statements)

References 35 publications

(57 reference statements)

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“…3(a). [42][43][44][45] The XPS results are consistent to XRD results of the sample prepared with 0.007 M of cobalt salt conrming the formation of cobalt ferrite structure rather than mixed phases of both CoO and Fe 2 O 3 . One can clearly observe the respective peaks for Fe 2p and Co 2p and O 1s which conrms these elements are presented in the sample.…”

Section: Xps Analysissupporting

confidence: 73%

“…The wide-scan XPS spectrum of the binding energies range from 0 to 850 eV for the sample prepared in the presence of 0.007 M of cobalt salt is presented in Fig. [42][43][44] The binding energy at $529 eV is attributed to the contribution of oxygen (O 1s). The binding energies of the particles were calibrated by taking the C 1s peak as reference ($285 eV).…”

Section: Xps Analysismentioning

confidence: 99%

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Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

Mosivand

Kazeminezhad

2015

RSC Adv.

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Cobalt ferrite nanopowders were synthesized by an electrocrystallization method. The synthesis was carried out in an electrochemical cell containing two iron electrodes, and an electrolyte solution of sodium sulfate, sodium butanoate, and cobalt sulphate heptahydrate. The concentration of the cobalt salt was optimized to produce cobalt ferrite nanoparticles. The samples were characterized by X-ray diffraction, XPS analysis, electron microscopy, magnetometry and Mössbauer spectroscopy. Based on XRD and XPS results we found that the cobalt ferrite nanoparticles are formed in the electrochemical cell containing 0.007 M cobalt sulphate heptahydrate. The nanoparticle size, shape, and morphology were characterized using electron microscopy. Electron microscope images of the samples show the mean particle size ranges from $7 nm to $90 nm. Magnetization curves of the samples show that the coercivity of the cobalt ferrite sample is about 0.04 T, which is much higher than the other samples.Based on our Mössbauer analysis it was found that increasing the concentration of cobalt, dramatically affects the subspectra. An increase in the hyperfine field and decrease in the population of octahedral sites provide direct evidence for the presence of the cobalt ions substitution in the octahedral sites.

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Section: Xps Analysissupporting

confidence: 73%

Section: Xps Analysismentioning

confidence: 99%

Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

Mosivand

Kazeminezhad

2015

RSC Adv.

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“…Mater. 2016, 26, 1954-1963 www.afm-journal.de www.MaterialsViews.com measured magnetization at saturation, M s , is 35 emu g −1 , which is in the reported range for nanoparticle CoFe 2 O 4 fi lms, [ 14 ] but lower than the bulk value of 80 emu g −1 . [ 31 ] Many factors contribute to a lowering in M s for nanocrystalline samples in comparison to the bulk, such as the difference in inversion parameters or the presence of a dead layer.…”

Section: Magnetic Characterization Of the Pure Cofe 2 O 4 Filmsmentioning

confidence: 62%

“…[ 10 ] Indeed, the presence of perpendicular magnetic anisotropy in thin fi lms is desired for high density perpendicular magnetic [ 13 ] and magneto-optical recording. With very few exceptions that involved sol-gel approaches, [ 14,15 ] such materials have typically been prepared via gas phase deposition methods, and the resulting perpendicular magnetic anisotropy relies on the epitaxy induced lattice strain coupling to the spins. [ 2,16 ] Unfortunately, in these cases the associated deposition rates are low and the equipment costs for manufacture are high.…”

Section: Introductionmentioning

confidence: 99%

CoFe₂O₄ and CoFe₂O₄‐SiO₂ Nanoparticle Thin Films with Perpendicular Magnetic Anisotropy for Magnetic and Magneto‐Optical Applications

Erdem

Bingham

Heiligtag

et al. 2016

Adv Funct Materials

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This paper presents an efficient colloidal approach to process CoFe2O4 and SiO2 nanoparticles into thin films for magnetic and magneto‐optical applications. Thin films of varying CoFe2O4‐to‐SiO2 ratios (from 0 to 90 wt%) are obtained by sequential spin coating‐calcination cycles from the corresponding nanoparticle dispersions. Scanning electron microscopy analysis reveals a crack free and nanoparticulate structure of the sintered films with thicknesses of 480–1200 nm. Results from the optical characterization indicate a direct band gap ranging from 2.6 to 3.9 eV depending on the SiO2 content. Similarly, the refractive indices and absorption coefficients are tunable upon SiO2 incorporation. In‐plane measurements of the magnetic properties of the CoFe2O4 films reveal a superparamagnetic behavior with both Co2+ and Fe3+ contributing to the magnetism. Polar Kerr measurements show the presence of a spontaneous magnetization in the CoFe2O4 and CoFe2O4‐SiO2 (with SiO2 < 50 wt%) films, pointing to magnetic anisotropy perpendicular to the substrate. The origin of this effect is attributed to the constrained sintering conditions of the nanoparticulate film and the negative magnetostriction of CoFe2O4.

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“…However, the X-ray photoelectron spectroscopy (XPS) patterns in Fig. 2(c) clearly reveal Co peaks, suggesting that CFO may also exist on the top layers 26,27 . Noting that XPS can only detect the top 10 nm of a sample, the fact that the XPS patterns revealed both Co and Bi peaks confirms that the CFO/BFO samples formed some type of self-assembled structure, although CFO and BFO were deposited in separate steps before annealing.…”

Section: Resultsmentioning

confidence: 99%

Magnetoelectricity of CoFe2O4 and tetragonal phase BiFeO3 nanocomposites prepared by pulsed laser deposition

Gao

Viswan

Tang

et al. 2018

Sci Rep

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The coupling between the tetragonal phase (T-phase) of BiFeO3 (BFO) and CoFe2O4 (CFO) in magnetoelectric heterostructures has been studied. Bilayers of CFO and BFO were deposited on (001) LaAlO3 single crystal substrates by pulsed laser deposition. After 30 min of annealing, the CFO top layer exhibited a T-phase-like structure, developing a platform-like morphology with BFO. Magnetic hysteresis loops exhibited a strong thickness effect of the CFO layer on the coercive field, in particular along the out-of-plane direction. Magnetic force microscopy images revealed that the T-phase CFO platform contained multiple magnetic domains, which could be tuned by applying a tip bias. A combination of shape, strain, and exchange coupling effects are used to explain the observations.

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Perpendicular magnetic anisotropy in 70nm CoFe2O4 thin films fabricated on SiO2/Si(100) by the sol–gel method

Cited by 31 publications

References 35 publications

Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

CoFe₂O₄ and CoFe₂O₄‐SiO₂ Nanoparticle Thin Films with Perpendicular Magnetic Anisotropy for Magnetic and Magneto‐Optical Applications

Magnetoelectricity of CoFe2O4 and tetragonal phase BiFeO3 nanocomposites prepared by pulsed laser deposition

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Perpendicular magnetic anisotropy in 70nm CoFe2O4 thin films fabricated on SiO2/Si(100) by the sol–gel method

Cited by 31 publications

References 35 publications

Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

Synthesis of electrocrystallized cobalt ferrite nanopowders by tuning the cobalt salt concentration

CoFe2O4 and CoFe2O4‐SiO2 Nanoparticle Thin Films with Perpendicular Magnetic Anisotropy for Magnetic and Magneto‐Optical Applications

Magnetoelectricity of CoFe2O4 and tetragonal phase BiFeO3 nanocomposites prepared by pulsed laser deposition

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CoFe₂O₄ and CoFe₂O₄‐SiO₂ Nanoparticle Thin Films with Perpendicular Magnetic Anisotropy for Magnetic and Magneto‐Optical Applications