Electric transport properties study of bulk BaFe12O19 by complex impedance spectroscopy

Pattanayak, Ranjit; Panigrahi, S.; Dash, Tapan; Muduli, Rakesh; Behera, D.

doi:10.1016/j.physb.2015.06.006

Cited by 76 publications

(17 citation statements)

References 47 publications

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“…boundary distortions, oxygen vacancies) unavoidably result in an incorporation into sitepositions of the lattice of small amounts of divalent iron. This was also shown by Pattanayak [54] for polycrystalline sample and confirmed by our terahertz spectroscopy on single crystalline BaM. Nevertheless, considering the suggested mechanisms that lead to the presence of Fe 2+ in BaM is definitely not sufficient to explain the tremendous dielectric contribution to low-energy dielectric constant in Ba 0.3 Pb 0.7 Fe 12 O 19 single crystals.…”

Section: Origin Of Terahertz Resonancessupporting

confidence: 83%

“…The largest cation (Ba 2+ , Pb 2+ or Sr 2+ ) occupies 12-coordinated 2d Wyckoff site-positon, and the Fe 3+ ions occupy 5 distinct sitepositions with different spin orientations-five-coordinated trigonal bi-pyramidal 2b, three non-equal octahedral 12k, 2a and 4f 2 , and one tetrahedral 4f 1 [53], see figure 10. A specific feature of the crystal structure of the M-type hexaferrites is the presence of ten-layered closely packed O 4 in polycrystalline BaFe 12 O 19 was confirmed by XPS study [54] and by chemical analysis in single crystals of BaFe 12 O 19 and PbFe 12 O 19 [55]. A small oxygen non-stoichiometry in the compounds can serve as 'source' of Fe 2+ ions in our samples.…”

Section: Origin Of Terahertz Resonancesmentioning

confidence: 57%

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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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Section: Origin Of Terahertz Resonancessupporting

confidence: 83%

Section: Origin Of Terahertz Resonancesmentioning

confidence: 57%

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

Alyabyeva¹,

Torgashev²,

Жукова³

et al. 2019

New J. Phys.

View full text Add to dashboard Cite

show abstract

“…8. However, this behavior has contributed to the presence of a third relaxation process at around 300 kHz different from the literature due to this higher Z 0 value [13,27].…”

Section: Ac Conductivitymentioning

confidence: 56%

“…When the external alternating electric field of frequency increases, the polarization decreases and reaches to a constant value because the electron exchange cannot follow the frequency. So, grain boundaries relaxation time will be higher than conducting grains [12,13,15,19,20]. Another important factor that affects electrical property of BaM is distribution of ferric ion (Fe 3þ ) in three crystallographically different sites, octahedral (12k, 2a, 4f 2 ), tetrahedral (4f 1 ) and pyramidal (2b) [15,20,22].…”

Section: Introductionmentioning

confidence: 99%

Maxwell-Wagner relaxation in grain boundary of BaBixLaxYxFe12−3xO19 (0.0 ≤ x ≤ 0.33) hexaferrites

Bakış

Auwal

Ünal

et al. 2016

Composites Part B: Engineering

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“…The imaginary modulus calculated by using the formula as: M 00 = xCoZ 0 where M = M' ? iM 00 [21]. Here, Co = e o A/t is the vacuum capacitance, e o = 8.85 9 10 -12 F/m is the permittivity of the free space, t is the thickness of the sample, and A is the crosssectional area of the electrode deposited on the sample and x is the angular frequency.…”

Section: Impedance and Modulus Studymentioning

confidence: 99%

Effect of grain size on electric transport and magnetic behavior of strontium hexaferrite (SrFe12O19)

et al. 2016

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Polycrystalline M-type hexagonal strontium hexaferrite (SrFe 12 O 19 ) was prepared by conventional ceramic route (LG SrM) and auto combustion (SG SrM) method. The single-phase pattern and well grain growth was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The average crystalline size is found to be 41.35 nm in LG SrM, while that of SG SrM is 36.87 nm. In this report, the electric transport behavior of LG SrM and SG SrM (SrFe 12 O 19 ) was successfully investigated and the analysis is done in the frequency range 100 Hz to 1 MHz at temperature 30-200°C. The relaxation behavior was examined by considering the impedance and modulus formalism in order to investigate the grain and grain boundary and surface polarization conduction process. The magnetic properties such as saturation magnetization, remanence, coercivity and anisotropy field are calculated from the hysteresis loop measurement. It was found that the saturation magnetization gets increased in LG SrM as compared to SG SrM system while the coercivity of SG SrM is greater than that of LG SrM.

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Electric transport properties study of bulk BaFe12O19 by complex impedance spectroscopy

Cited by 76 publications

References 47 publications

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

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

Maxwell-Wagner relaxation in grain boundary of BaBixLaxYxFe12−3xO19 (0.0 ≤ x ≤ 0.33) hexaferrites

Effect of grain size on electric transport and magnetic behavior of strontium hexaferrite (SrFe12O19)

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