Magnetic properties of Co-Ni spinel ferrite fine particles with high coercivity prepared by the chemical coprecipitation method

Yamamoto, Hiroshi; Nissato, Y.

doi:10.1109/tmag.2002.802717

Cited by 21 publications

(4 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1,[4][5][6] However, the low resistivity (10 4 Ω cm) and large crystalline anisotropy of cobalt ferrite make it unsuitable for some specific microwave and dielectric device applications, which instead require high resistivity and low crystalline anisotropy. 1,7,8 In order to modify the structural, magnetic and electronic properties of cobalt ferrite, partial substitution of nickel with respect to cobalt is a better choice as nickel ferrite exhibits the highest resistivity (∼10 9 Ω cm), low crystalline anisotropy (∼5 × 10 4 erg cm −3 ) and saturation magnetization (∼3000 Gauss). 1 Moreover, the inverse-spinel nickel ferrite has nearly the same Curie temperature as that of cobalt ferrite (860 K), and Ni 2+ and Co 2+ ions have nearly the same tetrahedral radius.…”

Section: Introductionmentioning

confidence: 99%

Observation of magnetic anomalies in one-step solvothermally synthesized nickel–cobalt ferrite nanoparticles

et al. 2016

View full text Add to dashboard Cite

Magnetic anomalies corresponding to the Verwey transition and reorientation of anisotropic vacancies are observed at 151 K and 306 K, respectively, in NiCoFe2O4 nanoparticles (NPs) synthesized by a modified-solvothermal method followed by annealing. Cationic disorder and spherical shape induced non-stoichiometry suppress the Verwey transition in the as-synthesized NPs. On the other hand, reorientation of anisotropic vacancies is quite robust. XRD and electron microscopy investigations confirm a single phase spinel structure and the surface morphology of the as-synthesized NPs changes from spherical to octahedral upon annealing. Rietveld analysis reveals that the Ni(2+) ions migrate from tetrahedral (A) to octahedral (B) sites upon annealing. The Mössbauer results show canted spins in both the NPs and the strength of superexchange is stronger in Co-O-Fe than Ni-O-Fe. Magnetic force images show that the as-synthesised NPs are single-domain whereas the annealed NPs are multi-domain octahedral particles. The FMR study reveals that both the NPs have a broad FMR line-width; and resonance properties are consistent with the random anisotropy model. The broad inhomogeneous FMR line-width, observation of the Verwey transition, tuning of the magnetic domain structure as well as the magnetic properties suggest that the NiCoFe2O4 ferrite NPs may be promising for future generation spintronics, magneto-electronics, and ultra-high-density recording media as well as for radar absorbing applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Observation of magnetic anomalies in one-step solvothermally synthesized nickel–cobalt ferrite nanoparticles

et al. 2016

View full text Add to dashboard Cite

show abstract

“…12,13) In contrast, a remarkably high coercive force of 6.37 kOe was obtained for CoNi spinel ferrite particles with the composition of (CoO) 0.5 (NiO) 0.5 ·1.125(Fe 2 O 3 ) prepared using a chemical co-precipitation method without post annealing. 14) Sugimoto et al reported a coercive force of 453.7 kA/m and saturation magnetization of approximately 43 Am 2 /kg in CoNi spinel ferrite particles. 15) We examined the possibility of achieving a high coercive force in the CoNi spinel ferrite particles and studied the mechanism that generates a high coercive force on the particular attention to apply the particles to permanent magnets.…”

Section: Introductionmentioning

confidence: 98%

Structure and Magnetic Properties of Co–Ni Spinel Ferrite Particles Synthesized via Co-Precipitation and Hydrothermal Treatment at Different Temperatures

et al. 2019

View full text Add to dashboard Cite

CoNi spinel ferrite particles were synthesized via chemical co-precipitation and subsequently performed hydrothermal treatment at different temperatures. Fine particles of size with a few nanometers and spherical or cubic particles of size approximately 30 nm, which are responsible for magnetic properties, were obtained. The crystallite size obtained using the Scherrer equation was 2427 nm and showed no dependency on the hydrothermal treatment temperature unlike the apparent particle size observed using transmission electron microscopy. The coercive force showed a remarkable increase with the decrease in the hydrothermal treatment temperature from 141 kA/m at 240°C to 400 kA/m at 100120°C, in contrast to the decrease in magnetization from 60.0 Am 2 /kg at 240°C to 37.2 Am 2 /kg at 100°C. The specific composition of the CoNi spinel ferrite particles is expected to affect the high coercive force and the remarkable dependency of the coercive force on the hydrothermal treatment temperature. [

show abstract

“…[15][16][17][18][19][20][21] Conversely, the coercive force of Co-Ni spinel ferrite particles reportedly shows a tendency to decrease with the substitution of Ni. [22][23][24] However, remarkably high coercive forces of 507 kA m −1 with the composition of (CoO) 0.5 (NiO) 0.5 •1.125(Fe 2 O 3 ), 25) and 453.7 kA m − 1 26) have been reported for Co-Ni spinel ferrite particles. Although the reasons for such a high coercive force in the Co-Ni spinel ferrite particles have not been clearly shown, the unique composition deviating from the stoichiometric spinel composition seems to be closely related to the high coercive force.…”

Section: Introductionmentioning

confidence: 99%

Coercive force of Co–Ni–Li spinel ferrite particles synthesized through co-precipitation, hydrothermal treatment, and etching in hydrochloric acid

Kishimoto¹,

Kita²,

Yanagihara³

2020

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

Co–Ni and Co–Ni–Li spinel ferrite particles were synthesized via chemical co-precipitation, hydrothermal treatment, and etching in hydrochloric acid. The particles were approximately 30 nm in size and showed typical XRD patterns of spinel structure with a lattice constant of 0.838 nm, similar to that in Fe3O4 crystals. The coercive force was 227 kA m−1 and 508 kA m−1 for Co–Ni and Co–Ni–Li spinel ferrite particles, respectively. The magnetic anisotropy field in Co–Ni–Li spinel ferrite particles estimated from rotational hysteresis losses was remarkably higher than that of Co–Ni spinel ferrite particles. Although the A- and B-sites in the spinel structure were considered to have been filled by metal ions in both particles, the positive charge calculated from the composition of Co–Ni–Li spinel ferrite particles was smaller than that in the Co–Ni spinel ferrite particles. Some defects introduced in the particles due to the composition may give some effects on the high coercive force.

show abstract

Magnetic properties of Co-Ni spinel ferrite fine particles with high coercivity prepared by the chemical coprecipitation method

Cited by 21 publications

References 18 publications

Observation of magnetic anomalies in one-step solvothermally synthesized nickel–cobalt ferrite nanoparticles

Observation of magnetic anomalies in one-step solvothermally synthesized nickel–cobalt ferrite nanoparticles

Structure and Magnetic Properties of Co–Ni Spinel Ferrite Particles Synthesized via Co-Precipitation and Hydrothermal Treatment at Different Temperatures

Coercive force of Co–Ni–Li spinel ferrite particles synthesized through co-precipitation, hydrothermal treatment, and etching in hydrochloric acid

Contact Info

Product

Resources

About