Microstructure and magnetic properties of Al-doped barium ferrite with sodium citrate as chelate agent

Chen, Daming; Liu, Yingli; Li, Yuanxun; Yang, Kai; Zhang, Huaiwu

doi:10.1016/j.jmmm.2013.02.036

Cited by 86 publications

(18 citation statements)

References 28 publications

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“…In the crystal structure of M type hexaferrite Fe 3þ ions are distributed in five different sites, three octahedral sites (12k, 4f 2 and 2a), one tetrahedral site (4f 1 ) and the last one is trigonal bipyramidal site (2b) [16]. Fe 3þ ions distributed on 12k, 2a and 2b sites have spin up electronic configuration, while those located on 4f 1 and 4f 2 sites have spin down electronic configuration [17]. Fe 3þ ions having magnetic moment of 5μB are substituted by Al 3þ ions having magnetic moment of 0 μB.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of aluminium substituted calcium hexaferrite

Shinde¹,

Dahotre

Singh

2020

Heliyon

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Al substituted M type Ca hexaferrite with composition CaAl x Fe 12-x O 19 (x ¼ 0, 0.2, 0.4, 0.6, 0.8) were synthesized by sol gel auto combustion method. The prepared samples were characterized by XRD, SEM, FTIR and VSM. X ray diffraction study shows that the with increasing aluminum ion concentration lattice parameter a decreases from 5.87 A to 5.83 A while the lattice parameter c decreases from 22.15 Å to 22.00 Å are well within the range of M type of hexaferrite. The crystallite size of the particles decreases from 74.36nm to 62.12nm are suitable for magnetic recording. Morphology of the particles from SEM images was hexagonal platelet. The absorption band between 580 and 440cm À1 in FTIR confirm the formation of hexaferrite. The magnetic properties of the samples changes with Al ion substitution make the material suitable for low density longitudinal and perpendicular magnetic recording.

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Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of aluminium substituted calcium hexaferrite

Shinde¹,

Dahotre

Singh

2020

Heliyon

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“…Subsequently, the temperature evolution of electromagnetic, thermodynamics, mechanical, calorimetric, etc properties of the pure barium hexaferrite BaFe 12 O 19 have been extensively investigated as described elsewhere [2]. The interest on these compounds was recently revived due to the possibility to manipulate their functional properties by inducing crystal field distortions with dopants [3][4][5][6][7][8][9][10][11][12][13][14]. In particular, the values of the coercive force [15], Curie temperature [16,17], magnetic permeability and the dielectric permittivity reveal strong changes caused by doping and chemical substitution [18].…”

Section: Introductionmentioning

confidence: 99%

Influence of chemical substitution on broadband dielectric response of barium-lead M-type hexaferrite

Alyabyeva¹,

Torgashev²,

Жукова³

et al. 2019

New J. Phys.

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We report on the electrodynamic properties of the single crystalline lead-substituted M-type barium hexaferrite, Ba 0.3 Pb 0.7 Fe 12 O 19 , performed in the broad frequency range including radio-frequency, terahertz and sub-terahertz bands, which are particularly important for the development of microelectronic devices. We demonstrate how changing on a molecular level the chemical characteristics (composition, intermolecular interaction, spin-orbital interaction) of lead-substituted M-type hexaferrite influences its radio-frequency and terahertz electrodynamic response. Our results indicate a critical temperature range, 50 K<T<70 K, where significant changes of the electrodynamic response occur that are interpreted as freezing of dynamical oscillations of bi-pyramidal Fe(2b) ions. In the range 5-300 K, the heat capacity shows no sign of any phase transition and is solely determined by electron and phonon contributions. An anomalous electrodynamic response is detected at 1-2 THz that features a rich set of absorption resonances which are associated with electronic transitions within the fine-structured Fe 2+ ground state and are visualized in the spectra due to magnetostriction and electron-phonon interaction. We show that lead substitution of barium in barium hexaferrite, BaFe 12 O 19 , leads to the emergence of a pronounced dielectric and magnetic relaxational dynamics at radio-frequencies and that both dynamics have the same characteristic relaxation times, thus evidencing the bi-relaxor-like nature of Ba 0.3 Pb 0.7 Fe 12 O 19 . We associate the origin of the relaxations as connected with the motion of magnetic domain walls. In order to unveil crucial influence of chemical substitution on electrodynamic characteristics of the compound, we analyze our results on substituted compound in comparison with the data available for pristine barium (BaFe 12 O 19 ) and pristine lead (PbFe 12 O 19 ) hexaferrites. The obtained spectroscopic data on the dielectric properties of Ba 0.3 Pb 0.7 Fe 12 O 19 provide insight into fundamental phenomena responsible for the absorption mechanisms of the compound and demonstrates that chemical ionic substitution is an effective tool to tune the dielectric properties of the whole family of hexaferrites.

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“…It is mainly attributed to M-type hexaferrites having large uniaxial magnetocrystalline anisotropy, excellent chemical stability and corrosion reistivity [3,4]. Thus, any further enhancement to the magnetic properties of Mtype hexaferrites is of relevance for technological innovation and larger market.…”

Section: Introductionmentioning

confidence: 99%