Scaling behavior of conductivity and magnetization in high-temperature superconductors

Wahl, A.; Hardy, V.; Warmont, F.; Maignan, A.; Delamare, M. P.; Simon, Ch.

doi:10.1103/physrevb.55.3929

Cited by 23 publications

(26 citation statements)

References 27 publications

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“…Therefore, away from the glass line, the two quantities have the LLL scaling as was demonstrated, for example, by several experiments on YBCO for both magnetization 55 and conductivity, 56 while near the glass line ͑experimentally determined in Ref. 57͒, the scaling is violated.…”

Section: Discussionmentioning

confidence: 83%

Quantitative theory of transport in vortex matter of type-II superconductors in the presence of random pinning

Rosenstein

Zhuravlev

2007

Phys. Rev. B

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We quantitatively describe the competition between interactions, thermal fluctuations, and random quenched disorder using the dynamical Martin-Siggia-Rose approach ͓Phys. Rev. A 8, 423 ͑1973͔͒ to the Ginzburg-Landau model of the vortex matter. The approach first used by Dorsey et al. ͓Phys. Rev. B 45, 523 ͑1992͔͒ to describe the linear response far from H c1 is generalized to include both pinning and finite voltage. It allows one to calculate the non-Ohmic I-V curve, thereby extending the theory beyond the linear response. The static flux line lattice in type-II superconductors undergoes a transition into three disordered phases: the vortex liquid ͑not pinned͒, the homogeneous vortex glass ͑pinned, if one disregards an exponentially small creep at finite tem-peratures͒, and the crystalline Bragg glass ͑pinned͒ due to both thermal fluctuations and disorder. The location of the glass transition line in the homogeneous phase is determined and compared to experiments. The line is clearly different from both the melting line and the second peak line describing the translational and rotational symmetry breaking at high and low temperatures, respectively. Time correlation and response functions of the order parameter as functions of the time difference are calculated in both the liquid and the amorphous homogeneous phases. They determine the relaxation properties of the vortex matter due to the combined effect of pinning and thermal fluctuation. We calculate the critical current as a function of magnetic field and temperature in the homogeneous phase. The surface in the J-B-T space defined by this function separates between a dissipative moving vortex matter regime and vortex glass. A quantitative theory of the peak effect, qualitatively different from the conventional one due to Pippard ͓C.

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Section: Discussionmentioning

confidence: 83%

Quantitative theory of transport in vortex matter of type-II superconductors in the presence of random pinning

Rosenstein

Zhuravlev

2007

Phys. Rev. B

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“…11 This is a typical behavior for highly anisotropic layered superconductors with a strong fluctuation effect. [12][13][14][15][16][17] Thermal fluctuations cause the magnetization curve to deviate from that predicted by the mean-field theory. 18 As a result, in the Hao-Clem model based on the Ginzburg-Landau theory, ͑T͒ increases unphysically near T c .…”

Section: Methodsmentioning

confidence: 99%

Effect of apical oxygen replacement by chlorine on the thermodynamic properties ofCa1.82Na0.18CuO2Cl2single crystals

Kim

et al. 2005

Phys. Rev. B

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We report the reversible magnetization of the Ca 2−x Na x CuO 2 Cl 2 ͑x = 0.18͒ single crystal for H ʈ c up to 1.2 T to study the effect of oxygen replacement by chlorine at the apical site. The superconducting transition temperature T c ͑ϳ27 K͒ of this single crystal is the highest reported in this family. Various thermodynamic parameters, such as the penetration depth ab ͑0͒, the coherence length ab ͑0͒, the critical field H c ͑0͒, the upper critical field H c2 ͑0͒ and the Ginzburg-Landau parameter , are also reported. Compared to the iso-structural compound La 1.82 Sr 0.18 CuO 4 with apical oxygen, Ca 1.82 Na 0.18 CuO 2 Cl 2 has two significant differences: ͑1͒ ab ͑0͒ is larger, so the Cooper pair density is quite reduced, and ͑2͒ the anisotropic nature is more enhanced. From these observations, chlorine at the apical site is thought to be less effective than oxygen in supplying charge carriers to the CuO 2 planes; as a result, the interlayer coupling between the CuO 2 planes is weakened.

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“…Cu 3 O 7−δ21,24 and La 2−x Sr x CuO4 25,26 among others. Several theoretical studies, based on the Ginzburg-Landau (GL) free energy, explain the appearance of the crossing point T * where the magnetization M * is independent of the field 22,23.…”

mentioning

confidence: 99%

“…The characteristic temperature (T * = 42.5 K) and magnetization (M * = -0.023 emu/cm 3 ) of this crossing point are marked on the graph. The crossing point in the magnetization vs. temperature curves is a distinctive feature of vortex fluctuations 19,20,21,22,23,24,25,26,27. Magnetization versus temperature curves for H parallel (panel A) and perpendicular (panel B) to the c-axis.…”

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confidence: 99%

Thermodynamic properties of excess-oxygen-dopedLa2CuO4.11near a simultaneous transition to superconductivity and long-range magnetic order

et al. 2004

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We have measured the specific heat and magnetization versus temperature in a single crystal sample of superconducting La2CuO4.11 and in a sample of the same material after removing the excess oxygen, in magnetic fields up to 15 T. Using the deoxygenated sample to subtract the phonon contribution, we find a broad peak in the specific heat, centered at 50 K. This excess specific heat is attributed to fluctuations of the Cu spins possibly enhanced by an interplay with the charge degrees of freedom, and appears to be independent of magnetic field, up to 15 T. Near the superconducting transition Tc(H=0)= 43 K, we find a sharp feature that is strongly suppressed when the magnetic field is applied parallel to the crystallographic c-axis. A model for 3D vortex fluctuations is used to scale magnetization measured at several magnetic fields. When the magnetic field is applied perpendicular to the c-axis, the only observed effect is a slight shift in the superconducting transition temperature.

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Scaling behavior of conductivity and magnetization in high-temperature superconductors

Cited by 23 publications

References 27 publications

Quantitative theory of transport in vortex matter of type-II superconductors in the presence of random pinning

Quantitative theory of transport in vortex matter of type-II superconductors in the presence of random pinning

Effect of apical oxygen replacement by chlorine on the thermodynamic properties ofCa1.82Na0.18CuO2Cl2single crystals

Thermodynamic properties of excess-oxygen-dopedLa2CuO4.11near a simultaneous transition to superconductivity and long-range magnetic order

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