Resistive transition and fluctuations of the conductivity in YBa2Cu3O7, EuBa2Cu3O7 and GdBa2Cu3O7 superconductors

Pureur, P.; Schaf, J.; Gusmao, Miguel Angelo Cavalheiro; Kunzler, J. V.

doi:10.1016/0921-4534(91)90038-z

Cited by 49 publications

(18 citation statements)

References 39 publications

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“…The resistivity peak is broadened under applied fields and diminished with increasing field as flux penetrates in the individual grains. It is also clear that, derivative of resistivity shows only one peak which is different from the Y(Ba 1−x Sr x ) 2 Cu 3 O 7−δ compound, in which two different peaks are seen clearly for inter and intra-grain with increase in applied field [14][15][16][17]. The broadening and separation of the peak increases with applied magnetic field and a broad peak is observed at low temperatures representing the intra-grain and inter-grain regimes [18].…”

Section: Resultsmentioning

confidence: 99%

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Meena

Pal

Kumar

et al. 2012

J Supercond Nov Magn

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Bulk polycrystalline samples, SmFeAsO and the iso-structural superconducting SmFeAsO 0.80 F 0.20 are explored through resistivity with temperature under magnetic field ρ(T, H), AC and DC magnetization (M-T), and Specific heat (C p ) measurements. The Resistivity measurement shows superconductivity for x = 0.20 sample with T c (onset) ~ 51.7K. The upper critical field, [H c2 (0)] is estimated ~3770kOe by Ginzburg-Landau (GL) theory. Broadening of superconducting transition in magneto transport is studied through thermally activated flux flow in applied field up to 130 kOe. The flux flow activation energy (U/k B ) is estimated ~1215K for 1kOe field. Magnetic measurements exhibited bulk superconductivity with lower critical field (H c1 ) of ~1.2kOe at 2K. In normal state, the paramagnetic nature of compound confirms no trace of magnetic impurity which orders ferromagnetically. AC susceptibility measurements have been carried out for SmFeAsO 0.80 F 0.20 sample at various amplitude and frequencies of applied AC drive field. The inter-granular critical current density (J c ) is estimated. Specific heat [C p (T)]measurement showed an anomaly at around 140K due to the SDW ordering of Fe, followed by another peak at 5K corresponding to the antiferromagnetic (AFM) ordering of Sm +3 ions in SmFeAsO compound. Interestingly the change in entropy (marked by the C p transition height) at 5K for Sm +3 AFM ordering is heavily reduced in case of superconducting SmFeAsO 0.80 F 0.20 sample .

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Section: Resultsmentioning

confidence: 99%

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Meena

Pal

Kumar

et al. 2012

J Supercond Nov Magn

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“…9 (a-e). It is well known that temperature derivative of resistivity gives narrow intense maxima centered at T c and broad peak at low temperatures representing intra-grain and inter-grain regimes [18][19][20][21]. In all plots [ Fig.…”

Section: Resultsmentioning

confidence: 99%

Magnetization and magneto-resistance in Y(Ba_1−xSr_x)₂Cu₃O_7−δ(x= 0.00–0.50) superconductors

Liyanawaduge

Singh

Kumar

et al. 2012

Supercond. Sci. Technol.

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Here we present the magnetic properties and upper critical field (B C2 ) of polycrystalline Y(Ba 1-x Sr x ) 2 Cu 3 O 7- superconductors, which are being determined through detailed ac/dc susceptibility and resistivity under magnetic field (RTH) study. All the samples are synthesized through solid state reaction route. Reduction in Meissner fraction (the ratio of field cooled to zero field cooled magnetization) is observed with increasing Sr content, suggesting occurrence of flux pining in the doped samples. The ac susceptibility and resistivity measurements reveal improved grain couplings in Sr substituted samples. Consequently the inter-grain critical current density (J c ), upturn curvature near the T c in temperature dependence of upper critical field [B C2 (T)], and B C2 are enhanced. Both J c and B C2 increase in lower Sr substitution (up to x = 0.10) samples followed by decrease in higher doping due to degradation in effective pining and grain coupling. PACS: 74.25.Wx, 74.25.fc, 74.25.Sv, 74.25.Op

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“…This is a thermally controlled percolation process, dependent on meso and macroscopic inhomogeneities. 23,24 In such case the pairing transition stabilizes the superconductivity into the grains and at a lower temperature T0 (see inset) a long-range coherent state is obtained, resulting in a zero electric resistivity. By comparing panels (a) and (c) for H = 0 and H = 1 T, respectively, is remarkable the strong broadening promoted by the magnetic field, where the difference in T0 is higher than 20 K. The results for TP and T0 are summarized in Table 1.…”

Section: Superconducting Transition and Dρ/dtmentioning

confidence: 99%

Gaussian and critical scalings in the magnetoconductivity fluctuations of Y₃Ba₅Cu₈O₁₈ superconductor

Dias

Vieira

Oliveira

et al. 2018

Int. J. Mod. Phys. B

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We have studied the superconducting transition and the magnetoconductivity fluctuations in the polycrystalline Y3Ba5Cu8O[Formula: see text] (Y358) superconductor under magnetic fields upto 1 T. A two-step superconducting transition could be observed as a consequence of the granular structure of the sample, which is strongly affected by the applied magnetic field. Gaussian and genuine critical 3D-XY-E fluctuation regimes were identified. A critical scaling regime beyond 3D-XY was identified for magnetic fields upto 0.25 T, corresponding to the averaged exponent 0.19 and suggesting the occurrence of the weak first-order character of the superconducting transition. In the approximation to the zero resistance a power law regime could be observed, corresponding to the averaged exponent 2.37, which are smaller than previously reported for the Y358 system. Our results are discussed in terms of the Y358 and YBa2Cu3O[Formula: see text](Y123) results in the literature.

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Resistive transition and fluctuations of the conductivity in YBa2Cu3O7, EuBa2Cu3O7 and GdBa2Cu3O7 superconductors

Cited by 49 publications

References 39 publications

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Magnetization and magneto-resistance in Y(Ba_1−xSr_x)₂Cu₃O_7−δ(x= 0.00–0.50) superconductors

Gaussian and critical scalings in the magnetoconductivity fluctuations of Y₃Ba₅Cu₈O₁₈ superconductor

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Resistive transition and fluctuations of the conductivity in YBa2Cu3O7, EuBa2Cu3O7 and GdBa2Cu3O7 superconductors

Cited by 49 publications

References 39 publications

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

Magnetization and magneto-resistance in Y(Ba1−xSrx)2Cu3O7−δ(x= 0.00–0.50) superconductors

Gaussian and critical scalings in the magnetoconductivity fluctuations of Y3Ba5Cu8O18 superconductor

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Magnetization and magneto-resistance in Y(Ba_1−xSr_x)₂Cu₃O_7−δ(x= 0.00–0.50) superconductors

Gaussian and critical scalings in the magnetoconductivity fluctuations of Y₃Ba₅Cu₈O₁₈ superconductor