Specific heat of high temperature superconductors in high magnetic fields

Junod, A.; Roulin, Marlyse; Revaz, B.; Mirmelstein, A.; Genoud, Jean-Yves; Wałker, E.; Erb, A.

doi:10.1016/s0921-4534(97)00794-6

Cited by 21 publications

(16 citation statements)

References 5 publications

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“…This is in agreement with recent specific heat measurements of anisotropy for highly oxygenated YBa 2 Cu 3 O 7Ϫ␦ . 12 A similar continuous change of anisotropy over a wide range of oxygen doping was observed for HgBa 2 CuO 4ϩ␦ . 21 The decrease in the anisotropy gives contribution to the observed change in the melting line.…”

Section: The Melting Line B M "T…supporting

confidence: 63%

“…1͑a͔͒ exhibit a kink at (T)/ n Ϸ0.08 representing the first order melting/freezing transition at T m between vortex solid and liquid states. 10,12,16 For larger fields, the kink is suppressed such that instead of dropping off sharply at T m the curves fall off gradually towards zero. Following Safar et al, 11 we have associated this fieldinduced broadening of the resistivity transition with the so called multicritical point, this being the point at which the first order melting transition is driven second order.…”

Section: Resultsmentioning

confidence: 99%

“…11 Very recent specific heat measurements have revealed that for BϾB mc the liquid-to-solid transition becomes second order. 12 It was also observed that decreases in ␦ drive the multicritical point to higher fields. However, specific heat measurements do not allow the vortex dynamics to be studied, thus mechanisms, which could be responsible for such transformations of the melting line, were not analyzed.…”

Section: Introductionmentioning

confidence: 96%

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Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
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Influence of the oxygen stoichiometry on the phase diagram of clean YBa 2 Cu 3 O 7Ϫ␦ single crystals has been studied in the region of optimal doping (0.05Ͻ␦Ͻ0.09). Temperature and angular dependencies of magnetoresistance were analyzed for fields of up to 23 T. At low fields a sharp resistivity kink, which is a signature of the first order melting transition, was observed in all the samples studied. This kink, however, disappears when B exceeds the multicritical field B mc . It was found that B mc strongly increases with decreasing ␦. We have demonstrated that variations in the oxygen stoichiometry in the range of 0.05Ͻ␦Ͻ0.09 do not have a significant effect on intrinsic parameters ͑such as anisotropy, coherence length, and penetration depth͒ but lead to a strong increase in entanglement of the vortex lines. We relate the dependence of B mc on ␦ with entanglement of the vortex lines, which is promoted by their interaction with oxygen vacancies.

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Section: The Melting Line B M "T…supporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
View full text Add to dashboard Cite

show abstract

“…Since α in (1) is very small, and 1/2ν ≈ 0.75, the two predictions are rather hard to distinguish. Some authors claim that lowest-Landau-level scaling works just as well as, or indeed better than, critical point scaling [15][16][17][18][19][20][21]. For HgBa 2 Ca 2 Cu 3 O 8+δ [22], specific heat data appear to collapse to a common curve when plotted in the form of (1), but the scaling function C(x), which ought to be universal, is apparently rather different from that found for YBCO.…”

Section: Introductionmentioning

confidence: 98%

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

Lee

Lawrie

2001

Phys. Rev. B

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If the zero-field transition in high temperature superconductors such as YBa 2 Cu 3 O 7−δ is a critical point in the universality class of the 3-dimensional XY model, then the general theory of critical phenomena predicts the existence of a critical region in which thermodynamic functions have a characteristic scaling form. We report the first attempt to calculate the universal scaling function associated with the specific heat, for which experimental data have become available in recent years. Scaling behaviour is extracted from a renormalization-group analysis, and the 1/N expansion is adopted as a means of approximation. The estimated scaling function is qualitatively similar to that observed experimentally, and also to the lowest-Landau-level scaling function used by some authors to provide an alternative interpretation of the same data. Unfortunately, the 1/N expansion is not sufficiently reliable at small values of N for a quantitative fit to be feasible. 64.60.Fr, 74.25.Bt

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“…The √ H dependence of the specific heat predicted by Volovik 1,2 and Kopnin and Volovik 3,4 was verified experimentally. [5][6][7] A detailed analysis of the data for H oriented perpendicular to the CuO 2 planes including impurity scattering was given by Kübert and Hirschfeld 8 (see also Barash et al 9 ). Transport properties were considered by Kübert and Hirschfeld.…”

Section: Introductionmentioning

confidence: 99%

Magnetic-field effects on the density of states of orthorhombic superconductors

Schachinger

Ćarbotte

1999

Phys. Rev. B

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The quasiparticle density of states in a two-dimensional d-wave superconductor depends on the orientation of the in-plane external magnetic field H. This is because, in the region of the gap nodes, the Doppler shift due to the circulating supercurrents around a vortex core depend on the direction of H. For a tetragonal system the induced pattern is four-fold symmetric and, at zero energy, the density of states exhibits minima along the node directions. But YBa 2 C 3 O 6.95 is orthorhombic because of the chains and the pattern becomes two-fold symmetric with the position of the minima occuring when H is oriented along the Fermi velocity at a node on the Fermi surface. The effect of impurity scattering in the Born and unitary limit are discussed. 74.20.Fg 74.25.Ha 74.72.-h Typeset using REVT E X

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Specific heat of high temperature superconductors in high magnetic fields

Cited by 21 publications

References 5 publications

Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
View full text Add to dashboard Cite

Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
View full text Add to dashboard Cite

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

Magnetic-field effects on the density of states of orthorhombic superconductors

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Specific heat of high temperature superconductors in high magnetic fields

Cited by 21 publications

References 5 publications

Phase diagram of optimally dopedYBa2Cu3O7Langan1, Gordeev2, Groot3 et al. 1998Phys. Rev. B16170View full textAdd to dashboardCite

Phase diagram of optimally dopedYBa2Cu3O7Langan1, Gordeev2, Groot3 et al. 1998Phys. Rev. B16170View full textAdd to dashboardCite

Critical-point scaling function for the specific heat of a Ginzburg-Landau superconductor

Magnetic-field effects on the density of states of orthorhombic superconductors

Contact Info

Product

Resources

About

Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
View full text Add to dashboard Cite

Phase diagram of optimally dopedYBa2Cu3O7
Langan
¹
,
Gordeev
²
,
Groot
³

et al. 1998
Phys. Rev. B
16
1
7
0
View full text Add to dashboard Cite