Waveform analysis of the voltage from a pick-up coil with a granular superconducting core: Critical state behavior

Gjølmesli, S.; Fossheim, K.

doi:10.1016/0921-4534(94)91128-2

Cited by 4 publications

(5 citation statements)

References 4 publications

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“…The necessity to consider j c (B) can be always avoided by application of a large DC field. In contrast, B d comparable with B a causes the effects created rather by a non-linear interaction between both of the fields, masking the intrinsic properties of the material , Gjomesli and Fossheim 1994a, Vuong 1996.…”

Section: Critical Current Density J Cmentioning

confidence: 94%

“…Various methods exist to analyse the pick-up coil voltage: the whole waveform can be analysed (e.g. Cave et al 1991, Gjomesli and Fossheim 1994b, Kerchner et al 1995, the waveform analyser can give the Fourier spectrum of the signal (e.g. Fabbricatore et al 1993a, Mazaki et al 1995 or, as the most simple way, only the effective value is detected by an AC voltmeter.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of high-temperature superconductors by AC susceptibility measurements

Gömöry

1997

Supercond. Sci. Technol.

290

197

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A magnetic field harmonically varying in time (to probe the sample) and a lock-in technique (to register the sample response sensed by a pickup coil) are widely used for characterizing superconductors. Measuring the temperature dependence of the complex AC susceptibility is the most common procedure of this type. This paper reviews these techniques, introducing in addition the complex AC susceptibility, the so-called 'wide-band AC susceptibility'. The latter quantity refers to the magnetic flux and often offers an easier meeting between theory and experiment. Starting from models for linear flux diffusion, reversible screening, volume and surface flux pinning and the intermediate regime in a type II superconductor, the expressions for the complex AC susceptibility in different cases are presented and compared with those derived for the wide-band AC susceptibility. Derivation of the basic physical properties of high-T c superconducting materials from the AC data (resistivity, critical temperatures and fields, London and Campbell penetration depths, critical current density, granularity and content of superconducting phase, irreversibility line, pinning potential) is then thoroughly discussed.

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Section: Critical Current Density J Cmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Characterization of high-temperature superconductors by AC susceptibility measurements

Gömöry

1997

Supercond. Sci. Technol.

290

197

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“…Ishida and Goldfarb [7] measured the complex harmonic susceptibilities of the sintered high-T c superconductor YBCO (123) in order to compare experimental results with theoretical susceptibility curves from the simplified Kim model. Gjolmesli and Fossheim [8] measured out of phase susceptibility as a function of temperature in the YBCO granular superconductors. Their model calculations, based on the simplified Kim-Anderson function for J c (H ), are given to support the interpretation of the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Characterization of high-T_csuperconductors using the higher-harmonic susceptibility

Ozogul

Aydinuraz

2001

Supercond. Sci. Technol.

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In the present work, the harmonic magnetic susceptibilities of the high-T c superconductors are examined and corresponding harmonic susceptibilities are calculated employing a model by Kim and coworkers. According to Kim's model, the critical-current density, J c is a function of the internal magnetic fieldwhere k and H o are constants. In the model calculations, full penetrations field, H p , is taken to beAs a result of the comparison of model calculations with experiments, we conclude that the harmonic susceptibilities for lower p values (p <10) correspond to the similar characteristic magnetic behaviour of granular superconductors, while the harmonic susceptibilities for higher p values correspond to the behaviour of homogeneous superconductors such as single crystal or samples with contiguous oriented grains.

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“…The two peak-effect in χ" has been previously observed in some (high temperature) granular superconductors investigated in superimposed ac-and dc-fields of approximately similar magnitude [10]. The interpretation of the two-peak effect is that one of these peaks is due to the intragrain loss, the other is due to intergrain loss.…”

Section: Single Crystalmentioning

confidence: 52%

On the nature of two superconducting transitions in the specific heat of PrOs$_4$Sb$_{12}$: Effects of crystal grinding

McBriarty,

Kumar,

Stewart

et al. 2007

Preprint

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Specific heat, dc-and ac-magnetic susceptibility are reported for a large single crystal of PrOs 4 Sb 12 and, after grinding, its powder. The room temperature effective paramagnetic moment of the crystal was consistent with the Pr 3+ ionic configuration and full occupancy of the Pr-sublattice. The crystal showed two distinct anomalies in the specific heat and an overall discontinuity in C/T of more than 1000 mJ/K 2 mol. The upper transition (at T c1 ) was rounded, in an agreement with previous reports. The anomaly at T c2 was very sharp, consistent with a good quality of the crystal. We observed a shoulder in χ' and two peaks in χ" below T c1 . However, there were no signatures in χ' of the lower temperature transition. PrOs 4 Sb 12 is extremely sensitive to grinding, which suppresses the upper superconducting transition in both the specific heat and magnetic susceptibility. ∆C/T c was reduced to 140 mJ/K 2 mol in the powdered sample. Existing data on ground, polished, and sliced crystals suggests the existence of a length scale of order 100 µ, characterizing the higher temperature superconducting phase.

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Waveform analysis of the voltage from a pick-up coil with a granular superconducting core: Critical state behavior

Cited by 4 publications

References 4 publications

Characterization of high-temperature superconductors by AC susceptibility measurements

Characterization of high-temperature superconductors by AC susceptibility measurements

Characterization of high-T_csuperconductors using the higher-harmonic susceptibility

On the nature of two superconducting transitions in the specific heat of PrOs$_4$Sb$_{12}$: Effects of crystal grinding

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Waveform analysis of the voltage from a pick-up coil with a granular superconducting core: Critical state behavior

Cited by 4 publications

References 4 publications

Characterization of high-temperature superconductors by AC susceptibility measurements

Characterization of high-temperature superconductors by AC susceptibility measurements

Characterization of high-Tcsuperconductors using the higher-harmonic susceptibility

On the nature of two superconducting transitions in the specific heat of PrOs$_4$Sb$_{12}$: Effects of crystal grinding

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Product

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Characterization of high-T_csuperconductors using the higher-harmonic susceptibility