Dielectric relaxation, resonance and scaling behaviors in Sr3Co2Fe24O41 hexaferrite

Tang, Rujun; Jiang, Chen; Qian, Wen‐Hu; Jian, Jie; Zhang, Xin; Wang, Haiyan; Yang, Hao

doi:10.1038/srep13645

Cited by 203 publications

(90 citation statements)

References 38 publications

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“…[20] The value close to 1 for the constant phase parameter n (see Table 1) indicates quite homogeneous properties of this layer. [27] However, our very thin hafnia thin films consist of mainly columnar grains [22] with a high fraction of oriented grain boundaries [17] strongly decreasing the grain boundary contribution. In literature, where other material systems and thicker layers are investigated, this is often interpreted as the difference between grains and grain boundaries.…”

Section: Wwwadvelectronicmatdementioning

confidence: 74%

“…The real and the imaginary parts of the impedance were plotted as a function of the temperature (see Figure 5). This can cause a piling-up of charge carriers in the low-conductive layer which causes the additional polarization for low frequencies, [27] similar to a Maxwell-Wagner relaxation. This behavior is well described in literature as nearly constant loss behavior caused by localized motions of dipoles in a double well potential.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

See 1 more Smart Citation

Analysis of Performance Instabilities of Hafnia‐Based Ferroelectrics Using Modulus Spectroscopy and Thermally Stimulated Depolarization Currents

Fengler

Nigon

Muralt

et al. 2018

Adv Elect Materials

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The discovery of the ferroelectric orthorhombic phase in doped hafnia films has sparked immense research efforts. Presently, a major obstacle for hafnia's use in high‐endurance memory applications like nonvolatile random‐access memories is its unstable ferroelectric response during field cycling. Different mechanisms are proposed to explain this instability including field‐induced phase change, electron trapping, and oxygen vacancy diffusion. However, none of these is able to fully explain the complete behavior and interdependencies of these phenomena. Up to now, no complete root cause for fatigue, wake‐up, and imprint effects is presented. In this study, the first evidence for the presence of singly and doubly positively charged oxygen vacancies in hafnia–zirconia films using thermally stimulated currents and impedance spectroscopy is presented. Moreover, it is shown that interaction of these defects with electrons at the interfaces to the electrodes may cause the observed instability of the ferroelectric performance.

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Section: Wwwadvelectronicmatdementioning

confidence: 74%

Section: Wwwadvelectronicmatdementioning

confidence: 99%

Analysis of Performance Instabilities of Hafnia‐Based Ferroelectrics Using Modulus Spectroscopy and Thermally Stimulated Depolarization Currents

Fengler

Nigon

Muralt

et al. 2018

Adv Elect Materials

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“…The log-log presentation of these complex impedance plot is represented for better clarity and comparison of the different impedance plots in a single plot. It can be noticed that the semi-circular arcs are distorted but logarithmic plots are superior in various aspects [50]. The presence of a CPE in the material sample reveals the multiphase character comprising of a microstructure having both crystalline, amorphous and a mixture of the two phases in the PS complex film [17,54].…”

Section: Complex Impedance Spectroscopy Analysismentioning

confidence: 99%

Effect of variation of different nanofillers on structural, electrical, dielectric, and transport properties of blend polymer nanocomposites

Arya

Sadiq

Sharma

2017

Ionics

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In the present work, the effect of different nanofiller (BaTiO3, CeO2, Er2O3 or TiO2) on blend solid polymer electrolyte comprising of PEO and PVC complexed with bulky LiPF6 have been explored. The XRD analysis confirms the polymer nanocomposite formation. FTIR provides evidence of interaction among the functional groups of the polymer with the ions and the nanofiller in terms of shifting and changing peak profile. The highest ionic conductivity is ~2.3×10 -5 S cm -1 with a wide electrochemical stability window of ~3.5 V for 10 wt. % Er2O3. The real and imaginary part of dielectric permittivity follows the identical trend of the decreasing value with increase in the frequency. The particle size and the dielectric constant shows an abnormal trend with different nanofiller. The ac conductivity follows the universal power law. An effective mechanism has been proposed to understand the nanofiller interaction with cation coordinated polymer in the investigated system. storage/conversion devices must have (a) high ionic conductivity; (b) electrochemical stability window (>4 V); (c) low melting point; (d) high boiling point; (e) high chemical stability; (f) nontoxicity; (g) low cost and good compatibility with electrodes. Solid polymer electrolyte (SPEs) plays a dual role as an electrolyte as well as a separator which keeps both electrodes separate and avoids the user from using a spacer as in liquid electrolyte system. The first report on ionic conduction was given by P. V. Wright [5] and Fenton et al [6] in 1973 and it was concluded that polymer host dissolved with an alkali metal salt results in an ionic conductive system. The first application of novel polymer electrolyte in batteries was announced by Armand and his co-workers in 1978 [7]. Most devices are based on liquid/gel polymer electrolytes due to their high ionic conductivity (10 -3 -10 -2 Scm -1 ) and compatible with electrodes. But poor mechanical strength, freezing at low temperature, leakage and flammable nature limits their application in commercial use. This motivates the researchers toward better replacement of liquid polymer electrolyte with a solvent free polymer electrolyte having high ionic conductivity, leak proof, flexibility, wide electrochemical window, good mechanical strength, light weight and ease of preparation [8-10]. Solid polymer electrolytes (SPEs) fulfill all above requirements and have attracted researchers globally towards development for their potential application in portable electronics and electrochemical devices [11]. The commonly used host polymer for preparation of polymer nanocomposite films (PNCs) is PEO [12], PAN [13], PMMA [14], PEMA [15] and PVC [16]. Out of aforesaid host polymers, polyethylene oxide (PEO) is undoubtedly the best host polymer used as SPEs with strong, unstrained C-O, C-C, C-H bonds and it has high dielectric constant, easy availability, and high ionic conductivity in amorphous phase, low glass transition temperature, high flexibility, and good dimensional and chemical stability. But PEO possesses low ion...

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“…[38] The results indicate the analogy with the previous reports where the pyridinic and graphitic content increase with the annealing. [39][40] The formation of Fe 2 + and Fe 3 + is observed in FeÀ N-GVC and Fe/2CoÀ N-GVC, whereas Co 2 + is present in the CoÀ N-GVC and Fe/2CoÀ N-GVC composites.…”

Section: Resultsmentioning

confidence: 99%

Medium Modulated Oxygen Reduction Activity of Fe/Co Active Centre‐engrafted Electrocatalysts

et al. 2019

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Iron and cobalt metal atoms are effective active centers for the synthesis of carbon-based noble-metal-free catalysts for the oxygen reduction reaction (ORR) owing to their cost-effective intrinsic activity and tunable properties. Annealing of the active center with the conducting carbon enhances the ORR activity significantly. Herein, we have engrafted Fe and Co active centers in the homemade conducting carbon and the ORR performance has been closely observed under acidic and basic pH conditions to understand the influence of the medium and participating moieties towards the performance. In the half-cell reaction, the onset potential and half-wave potential for ORR are governed by the surface intermediates and concomitantly driven by the adsorption energies of the intermediates over the active centers. The iron and cobalt active center-engrafted carbon catalyst behaves differently in acidic and basic electrolytes owing to the dissociation of the surface intermediates. The iron-based catalyst shows improved onset potential against the cobalt-based one. Similarly, the cobalt-based catalyst shows improved half-wave potential against the iron active-centergrafted catalyst. The combined synergistic effect of the two catalysts is realized in the composition represented as Fe/ 2CoÀ N-GVC, where improved onset and half-wave potentials are noted in basic medium. A significant variation in the activity of the catalyst is observed as the medium changes from acidic to basic and the effect is directly associated with the surface adsorption of the intermediates.[a] V.

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Dielectric relaxation, resonance and scaling behaviors in Sr3Co2Fe24O41 hexaferrite

Cited by 203 publications

References 38 publications

Analysis of Performance Instabilities of Hafnia‐Based Ferroelectrics Using Modulus Spectroscopy and Thermally Stimulated Depolarization Currents

Analysis of Performance Instabilities of Hafnia‐Based Ferroelectrics Using Modulus Spectroscopy and Thermally Stimulated Depolarization Currents

Effect of variation of different nanofillers on structural, electrical, dielectric, and transport properties of blend polymer nanocomposites

Medium Modulated Oxygen Reduction Activity of Fe/Co Active Centre‐engrafted Electrocatalysts

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