E–J characteristics of NdBa2Cu3O7−δ bulk superconductor determined with ac susceptibility

Inoue, Kazuo; Sakai, Naomichi; Waki, Koichiro; Murakami, Masato

doi:10.1016/s0921-4534(01)00343-4

Cited by 12 publications

(7 citation statements)

References 5 publications

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“…Figure 4(b) shows the real and imaginary parts of the third harmonics of the studied sample at various frequencies. The frequency dependence of the third harmonics of FeSe 0.5 Te 0.5 is similar to the previously reported LaFeAsO 0.92 F 0.08 superconductor [28]. It is obvious from figure 4(b) that 3 rd harmonic components are even more sensitive to the frequency variation.…”

Section: Ac Magnetic Response At Different Frequenciessupporting

confidence: 87%

“…It is clear from the inset of figure 4(a) that the height of the peak χ″ 1 (T p ) grows as we increase the frequency which indicates that the studied system is in a Vortex glass phase. A similar splitting effect is also observed in polycrystalline Fe 1.02 Se and LaFeAsO 0.92 F 0.08 samples [14,28].…”

Section: Ac Magnetic Response At Different Frequenciessupporting

confidence: 80%

“…Generally, high T c superconductors show two different peaks in the imaginary part of complex susceptibility, which are accounted for the inter-and intra-granular transitions. In the currently studied sample, we do not observe any separate peak at lowest applied ac field also [28]. Thus, we can neglect the effect of granularity in the sample, or one can say that due to the strong inter-granular coupling, the transition from inter-and intra-grain components merge into each other.…”

Section: B Ac Magnetic Response At Different H Ac Amplitudesmentioning

confidence: 68%

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Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Pal

Rani

Hafiz

et al. 2019

Mater. Res. Express

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We present the complex harmonic magnetic susceptibilities χ n = χ′ n -iχ″ n (n = 1, 3) of the FeSe 0.5 Te 0.5 polycrystalline superconducting sample. The ac magnetic susceptibility is measured as a function of various external perturbations such as temperature T, the ac magnetic field amplitude H ac , frequency υ, and the magnitude of dc bias field H dc . The inphase (χ′ n ) and out of phase (χ″ n ) components of the fundamental and third harmonics of ac susceptibility are found to vary as a function of the ac drive field. Particularly, the curves shift to lower temperatures with increasing H ac . Contrary to ac magnetic field H ac , no noticeable change has been observed within the range of the applied dc magnetic field of H dc = 0 Oe to 20 Oe. At a fixed ac field, H ac = 0.5 Oe both parts of the third harmonics show the frequency dependence. The imaginary part of third harmonics, χ″ 3 shows two peaks as a function of frequency, one negative in magnitude and another is positive. The negative peak shifts towards the lower temperature and positive peak are shifted towards the higher temperature as we increase the frequency. To better understand the ac magnetic response under the influence of various perturbations, we have analyzed the polar plots (Cole-Cole) of the complex ac susceptibility for both the harmonics. Our analysis suggests that the studied sample is in a vortex glass state, characterized by a collective flux creep within Bean's model and the Kim-Anderson model is ruled out.

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Section: Ac Magnetic Response At Different Frequenciessupporting

confidence: 87%

Section: Ac Magnetic Response At Different Frequenciessupporting

confidence: 80%

Section: B Ac Magnetic Response At Different H Ac Amplitudesmentioning

confidence: 68%

See 1 more Smart Citation

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Pal

Rani

Hafiz

et al. 2019

Mater. Res. Express

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“…The vortex diffusion in the superconductor can be either linear (FF or TAFF) or nonlinear process (FC), depending on the interrelation H H dc ac [62,63,89]. Thus, the higher harmonics also provide excellent insight into the nature of the dissipative processes, which determine the shape of the E J ( ) characteristics [90][91][92]. The presence of the different dynamical regimes influences the ac magnetic response of the superconductor and leads to very complex shapes of the harmonic curves [60][61][62][63].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the vortex dynamics of Fe_1.02Se crystals by fundamental and 3rd harmonic ac magnetic susceptibility analysis

Buchkov

Polichetti

Nenkov

et al. 2015

Supercond. Sci. Technol.

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The superconducting properties of mm-sized Fe1.02Se crystals grown by a flux method are investigated. The structural and morphological features are studied by x-ray diffraction (XRD) and by scanning electron microscopy-energy dispersive x-ray spectroscopy SEM-EDX analysis, which identified a co-growth of a dominant superconducting tetragonal phase, with the minority of a non-superconducting hexagonal phase. The ac magnetic response is analyzed using a combined method of the fundamental and the 3rd harmonic ac magnetic susceptibility as a function of the temperature at different ac magnetic field amplitudes and frequencies and with various superimposed dc fields. The variation of the ac magnetic field and frequency in different ranges especially affects the 3rd harmonic components, which are more sensitive to the changes in the flux dynamic regimes. This allows a fine observation of the evolution of the different linear and non-linear processes responsible for the ac magnetic response of the Fe1.02Se crystals. At low enough ac amplitudes and frequencies, and even in high imposed dc magnetic fields, the Fe1.02Se crystals show a typical critical state behavior, marking a high stability of the pinning, with very small influence of the vortex dynamical processes. With the change of ac field amplitude and frequency a gradual crossover is observed from the initial stable pinning state through the domination of the intermediate regimes as flux creep and finally to the complete dominance of flux flow. The ac magnetic response is also influenced by geometric edge barrier effects arising from the plate-like geometry of the Fe1.02Se crystals. The changes of the dominant irreversible (non-linear) mechanism from surface pinning to bulk pinning or to prevailing dynamical regimes is also identified by analyzing the behavior of the 3rd harmonic components.

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“…Therefore, they are highly dependent on the selected experimental parameters such as field sweep rate, and especially on the frequency in the case of ACMS. In the last case, the irreversible process contribution to the AC magnetic response will come mostly from the flux pinning but the effect of flux creep will be strong as well [59,60] been investigated. The results are presented in figure 6 with a notable double peak structure, which is very prominent at 6 T. This allows the construction of the key irreversibility field lines and the phase transitions by considering the pseudopeak temperature position at different fields as well as with the intrinsic irreversibility line marked by the appearance/ disappearance of the third harmonic signal.…”

Section: Resultsmentioning

confidence: 99%

Harmonic AC magnetic susceptibility analysis of FeSe crystals with composite morphology

et al. 2019

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The AC magnetic response of multi-domain FeSe crystals has been explored by means of fundamental and third harmonic AC magnetic susceptibility (ACMS) analysis. Our previous studies have revealed a complex morphology which especially modifies the mixed state properties. The effects were expressed by an additional 'pseudo' peak feature of the magnetic hysteresis and in the present study we analyze its vortex dynamics nature and irreversibility behavior in the context of ACMS. We find that the effect is detectable mainly with the sensitive third harmonic component and especially at high AC field frequencies. From the analysis, the temperature dependence of the 'pseudo' peak effect at different DC fields ranges was determined, confirming the previously established superconductor-normal metal-superconductor type links between the domains in the crystal. The irreversibility line, the most important parameter for high power applications, shows a typical glass/liquid transition in the vortex matter. In addition we have observed surface barrier effects and vortex avalanche activity, the behavior of which appears to be influenced by the superconducting and magnetic nature coexistence and morphology. The presented results show the effective application of the harmonic AC magnetic susceptibility technique for a versatile analysis of complex nonlinear phenomena in materials with a sophisticated AC magnetic response.

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E–J characteristics of NdBa2Cu3O7−δ bulk superconductor determined with ac susceptibility

Cited by 12 publications

References 5 publications

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Investigation of the vortex dynamics of Fe_1.02Se crystals by fundamental and 3rd harmonic ac magnetic susceptibility analysis

Harmonic AC magnetic susceptibility analysis of FeSe crystals with composite morphology

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E–J characteristics of NdBa2Cu3O7−δ bulk superconductor determined with ac susceptibility

Cited by 12 publications

References 5 publications

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe0.5Te0.5 superconductor

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe0.5Te0.5 superconductor

Investigation of the vortex dynamics of Fe1.02Se crystals by fundamental and 3rd harmonic ac magnetic susceptibility analysis

Harmonic AC magnetic susceptibility analysis of FeSe crystals with composite morphology

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Product

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Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Investigation of fundamental and higher harmonic AC magnetic susceptibility of FeSe_0.5Te_0.5 superconductor

Investigation of the vortex dynamics of Fe_1.02Se crystals by fundamental and 3rd harmonic ac magnetic susceptibility analysis