Competition Between Structural and Superconducting Transition in (LaNd)-Sr-Cu-O

Büchner, B.; Cramm, M.; Braden, M.; Braunisch, W.; Hoffels, O.; Schnelle, Walter; Müller, Ralf; Freimuth, A.; Schlabitz, W.; Heger, G.; Khomskiî, D. I.; Wohlleben, D.

doi:10.1209/0295-5075/21/9/013

Cited by 57 publications

(24 citation statements)

References 28 publications

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“…This breaking found in optimally and overly doped LSCO is consistent with previous results obtained by other techniques [17][18][19][20] suggesting competition between the structural phase transition and the superconductivity in LSCO and related compounds. Such a competition is also seen in other systems such as the A15 superconductors.…”

Section: A Soft Phononssupporting

confidence: 92%

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

et al. 2000

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Comprehensive inelastic neutron-scattering measurements were performed to study the soft optical phonons in La2−xSrxCuO4 at x = 0.10, 0.12 and 0.18. We found at x = 0.18 that the softening of Z-point phonon, suggesting incipient structural transition from the low-temperature orthorhombic (LTO) to low-temperature tetragonal (LTT) phase, breaks at Tc, which is consistent with the previous report by Lee et al. for the optimally doped x = 0.15 sample. As for x = 0.10 and 0.12, on the other hand, the softening continues even below Tc. It is thus clarified that the breaking of soft phonon is characteristic of La2−xSrxCuO4 in the optimally and overdoped regions. In the course of studying the soft phonons, we discovered that a central peak remains above the LTO to high-temperature tetragonal (HTT) phase transition at Ts1 and splits into incommensurate components along the (1 1 0)HTT direction at higher temperatures. This is a common feature for both x = 0.12 and 0.18 and their temperature dependences of the splitting 2δ can be scaled by using a renormalized temperature T /Ts1. In the high temperature limit, δ saturates around δ ∼ 0.12 r.l.u., which value is close to the splitting of incommensurate magnetic signals. This implies that the incipient lattice modulation starts appearing at very high temperature. Details of this modulation and its relations with other properties are, however, not yet clarified.

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Section: A Soft Phononssupporting

confidence: 92%

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

et al. 2000

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“…Taking the resolution into account, we estimate a typical domain size of ∼ 1000Å or greater. The LTT peak observed in this crystal is considerably sharper than those typically detected in powder samples, 2,4,31 where the LTT peak width is comparable to the LTO splitting. The broad peaks observed in powders raised concerns that the superconductivity which appears to survive in the LTT phase 20,21,22 might actually be associated with small LTO domains.…”

Section: Lto-to-ltt Transitionmentioning

confidence: 47%

Glassy nature of stripe ordering inLa1.6−xNd0.4Sr
Tranquada
¹
,
Ichikawa
²
,
Uchida
³

1999
Phys. Rev. B
157
19
119
0
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We present the results of neutron-scattering studies on various aspects of crystalline and magnetic structure in single crystals of La1.6−xNd0.4SrxCuO4 with x = 0.12 and 0.15. In particular, we have reexamined the degree of stripe order in an x = 0.12 sample. Measurements of the width for an elastic magnetic peak show that it saturates at a finite value below 30 K, corresponding to a spin-spin correlation length of 200Å. A model calculation indicates that the differing widths of magnetic and (previously reported) charge-order peaks, together with the lack of commensurability, can be consistently explained by disorder in the stripe spacing. Above 30 K (i.e., above the point at which a recent muon spin-rotation study has found a loss of static magnetic order), the width of the nominally elastic signal begins to increase. Interpreting the signal as critical scattering from slowly fluctuating spins, the temperature dependence of the width is consistent with renormalized classical behavior of a 2-dimensional anisotropic Heisenberg antiferromagnet. Inelastic scattering measurements show that incommensurate spin excitations survive at and above 50 K, where the elastic signal is neglible. Given that the stripe order is believed to be pinned by the low-temperature tetragonal (LTT) crystal structure, we have also investigated the transition near 70 K from the low-temperature orthorhombic (LTO) structure. We show that our x = 0.12 crystal passes through an intervening less-orthorhombic phase, before reaching the LTT at ∼ 40 K, whereas the x = 0.15 crystal goes directly from LTO to LTT, with coexistence of the two phases over a range of ∼ 7 K. Sharp Bragg peaks in the LTT phase of the x = 0.15 crystal indicate a domain size of > ∼ 1000Å, with no obvious evidence for LTO domains; hence, the coexistence of stripe order and superconductivity in this sample cannot be explained by a mixture of crystalline phases. Finally, we present scattering evidence for small LTT-like domains in the LTO phase of the x = 0.15 sample. A correlation between the volume fraction of such domains and deviations of in-plane resistivity from linear T dependence suggest that charge stripes interact with these domains within the LTO matrix.75.50. Ee, 75.30.Fv, 71.45.Lr, 71.27+a

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“…In the case of stripe order, these materials exhibit stripe-like arrangements of alternating hole-rich and antiferromagnetic regions, where in all these materials an intimate interplay between structure, stripe order and superconductivity is present. More specifically, bulk superconductivity is suppressed in favor of static stripe order where the latter is stabilized through a particular tilting pattern of the CuO 6 octahedra in the lowtemperature tetragonal structural phase (LTT-phase) [23,38,47,52,53,54]. In the prototype stripe ordering compound La 2−x Ba x CuO 4 the LTT phase is only present in a limited doping range around x = 1/8 [55].…”

Section: Nernst Effect and Sdw Fluctuations In The Iron-based Supercomentioning

confidence: 99%

Nernst Effect of Iron Pnictide and Cuprate Superconductors: Signatures of Spin Density Wave and Stripe Order

Heß

2012

NATO Science for Peace and Security Series B: Physics and Biophysics

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The Nernst effect has recently proven a sensitive probe for detecting unusual normal state properties of unconventional superconductors. In particular, it may sensitively detect Fermi surface reconstructions which are connected to a charge or spin density wave (SDW) ordered state, and even fluctuating forms of such a state. Here we summarize recent results for the Nernst effect of the iron pnictide superconductor LaO 1−x F x FeAs, whose ground state evolves upon doping from an itinerant SDW to a superconducting state, and the cuprate superconductor La 1.8−x Eu 0.2 Sr x CuO 4 which exhibits static stripe order as a ground state competing with the superconductivity. In LaFeAsO 1−x F x , the SDW order leads to a huge Nernst response, which allows to detect even fluctuating SDW precursors at superconducting doping levels where long range SDW order is suppressed. This is in contrast to the impact of stripe order on the normal state Nernst effect in La 1.8−x Eu 0.2 Sr x CuO 4 . Here, though signatures of the stripe order are detectable in the temperature dependence of the Nernst coefficient, its overall temperature dependence is very similar to that of La 2−x Sr x CuO 4 , where stripe order is absent. The anomalies which are induced by the stripe order are very subtle and the enhancement of the Nernst response due to static stripe order in La 1.8−x Eu 0.2 Sr x CuO 4 as compared to that of the pseudogap phase in La 2−x Sr x CuO 4 , if any, is very small.

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Competition Between Structural and Superconducting Transition in (LaNd)-Sr-Cu-O

Cited by 57 publications

References 28 publications

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

Glassy nature of stripe ordering inLa1.6−xNd0.4Sr
Tranquada
¹
,
Ichikawa
²
,
Uchida
³

1999
Phys. Rev. B
157
19
119
0
View full text Add to dashboard Cite

Nernst Effect of Iron Pnictide and Cuprate Superconductors: Signatures of Spin Density Wave and Stripe Order

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Competition Between Structural and Superconducting Transition in (LaNd)-Sr-Cu-O

Cited by 57 publications

References 28 publications

Structural Instability Associated with the Tilting of CuO6Octahedra in La2-xSrxCuO4

Structural Instability Associated with the Tilting of CuO6Octahedra in La2-xSrxCuO4

Glassy nature of stripe ordering inLa1.6−xNd0.4SrTranquada1, Ichikawa2, Uchida3 1999Phys. Rev. B157191190View full textAdd to dashboardCite

Nernst Effect of Iron Pnictide and Cuprate Superconductors: Signatures of Spin Density Wave and Stripe Order

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About

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

Structural Instability Associated with the Tilting of CuO₆Octahedra in La_2-xSr_xCuO₄

Glassy nature of stripe ordering inLa1.6−xNd0.4Sr
Tranquada
¹
,
Ichikawa
²
,
Uchida
³

1999
Phys. Rev. B
157
19
119
0
View full text Add to dashboard Cite