Magnetic penetration depth and fluxon-line dynamics in the organic superconductor κ-[BEDT-TTF<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Cu[NCS<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>]</mml:mo></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Harshman, Dale R.; Fiory, A. T.; Haddon, Robert C.; Kaplan, M. L.; Pfiz, T.; Köster, E.; Shinkoda, I.; Williams, Dudley

doi:10.1103/physrevb.49.12990

Cited by 46 publications

(22 citation statements)

References 55 publications

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“…More importantly, figure 4(b) of [66] shows a minimum in ΔB(T) at ~5 K, in direct correspondence to the associated anomaly in |ΔB(T)| 2 , and similar to that observed for Bi 2 Sr 2 CaCu 2 O 8+δ [28].…”

Section: Fluxon Pinning and Thermal Depinningmentioning

confidence: 52%

“…It is also worth noting that the κ-[BEDT-TTF] 2 Cu[NCS] 2 data from [66] were acquired in a transverse field of 129 Oe, and exhibit a T C consistent with 10.5 K, whereas data taken earlier [67] at a higher field of 0.3 T present a depressed T C , reflecting a trend consistent with fluxon dynamics in the presence of high Γ. More importantly, figure 4(b) of [66] shows a minimum in ΔB(T) at ~5 K, in direct correspondence to the associated anomaly in |ΔB(T)| 2 , and similar to that observed for Bi 2 Sr 2 CaCu 2 O 8+δ [28].…”

Section: Fluxon Pinning and Thermal Depinningmentioning

confidence: 99%

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Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

Harshman¹,

Fiory²

2011

J. Phys.: Condens. Matter

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Muon spin rotation (μ + SR) measurements of square-root second moments of local magnetic fields σ in superconducting mixed states, as published for oriented crystals and powder samples of YBa 2 Cu 3 O 7-δ (  0.05), YBa 2 Cu 4 O 8 and La 2x Sr x CuO 4 (x ~ 0.15-0.17), are subjected to comparative analysis for superconducting gap symmetry. For oriented crystals it is shown that anomalous dependences of σ on temperature T and applied field H, as-measured and extracted a-and b-axial components, are attributable to fluxon depinning and disorder that obscure the intrinsic character of the superconducting penetration depth. Random averages derived from oriented-crystal data differ markedly from corresponding non-oriented powders, owing to weaker influence of pinning in high-quality crystals. Related indicators for pinning perturbations such as non-monotonic H dependence of σ, irreproducible data and strong H dependence of apparent transition temperatures are also evident. Strong intrinsic pinning suppresses thermal anomalies in c-axis components of σ, which reflect nodeless gap symmetries in YBa 2 Cu 3 O 7-δ and YBa 2 Cu 4 O 8 . For YBa 2 Cu 3 O 7-δ , the crystal (a-b components, corrected for depinning) and powder data all reflect a nodeless gap (however, a-b symmetries remain unresolved for crystalline YBa 2 Cu 4 O 8 and La 1.83 Sr 0.17 CuO 4 ). Inconsistencies contained in multiple and noded gap interpretations of crystal data, and observed differences between bulk μ + SR and surface-sensitive measurements are discussed.

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Section: Fluxon Pinning and Thermal Depinningmentioning

confidence: 52%

Section: Fluxon Pinning and Thermal Depinningmentioning

confidence: 99%

Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

Harshman¹,

Fiory²

2011

J. Phys.: Condens. Matter

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“…Clearly BaO layers or SrO layers superconduct. (We shall see that, in some cases, interstitial oxygen superconducts [13] [14], and in some organic compounds [34], sulfur chains carry the superconducting holes. )…”

Section: Gdba 2 Cu 3 0 7 Compoundsmentioning

confidence: 88%

BaO PLANES, NOT CuO₂ PLANES, CONTAIN HIGH-T_C SUPERCONDUCTIVITY

Dow

Harshman

2007

Int. J. Mod. Phys. B

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Muon spin rotation (p SR) measurements conducted on crystalline YBa 2 Cu 3 0 7 are consistent with s-wave pairing, not rf-wave, suggesting that the superconducting hole condensate resides in the BaO layers, not in the cuprate-planes. The specific heat and thermal conductivity data are explained by the superconducting BaO layers alone, unlike the failed interpretation based on Cu0 2 -plane superconductivity. The layer charges of the Cu0 2 planes are almost -2 lel, indicating that those planes are primarily carriers of electrons, not holes. The cuprate-planes are not the dominant hole-carriers of high-T c superconductivity, as demonstrated by doped YBa 2 Ru0 6 , which has no such Cu0 2 lanes, yet superconducts at ~ 93 K. Moreover the trio of related compounds, YSr 2 Ru0 6 (doped with Cu on Ru sites), undoped GdSr 2 Cu 2 Ru0 8 , and undoped Gd 2 _ ;: Ce ; ,Sr 2 Cu 2 RuOio all start superconducting near 49 K in their SrO layers, not in the cuprate planes of the two compounds that have such planes, because those planes are either antiferromagnetic or weakly ferromagnetic and so do not superconduct. In PrBa 2 Cu 3 0 7 , a Pr-on-Ba-site (Pr Ba ) defect kills the superconductivity, but Pr-on-Pr-site (Pr Pr ) does not. Both defects are approximately equidistant from the intervening cuprate plane, suggesting that the cuprate plane does not carry significant superconductivity. In GdBa 2 Cu 3 0 7 , Gd-on-a-Gd-site (Gd Gi ) does not break Cooper pairs, but Gd-on-a-Ba-site (Gd Ba ) does, indicating that the superconductivity is in the BaO layers, and not in the cuprate-planes. In HgBa 2 Ca"_ 1 Cu"0 2 " +2 , the BaO layers, not the cuprate-planes, gain positive charge as T C , pressure, and the number of layers n increase. The reason that theories based on holes in the cuprate-planes have done so poorly is that those planes were incorrectly identified as the source of high-temperature superconductivity on the basis of a single datum by Cava et al., that was first contradicted by Jorgensen et al., and then endorsed by Jorgensen alone on the basis of the Cava datum, not his own. This error is the main reason why cuprate-plane superconductivity, which probably does not exist, has been so widely accepted.

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“…Early studies 85 showed that the ground-state symmetry was s wave and the basal-plane magnetic penetration depth was in the range 5100-9800 Å. 86 Later experiments 84 have set the London penetration depth at 7680± 700 Å and have confirmed the s-wave character of the gap function with a precision of 3%. Not surprisingly the superconducting transition temperatures of these materials are comparatively low ͑i.e., of order 10 K͒.…”

Section: Organic Superconductorsmentioning

confidence: 90%

“…84 In this case, the holes conduct in the bc plane along twodimensional sulfur chains in the middle of the BEDT-TTF cations, which are separated by the Cu͓NCS͔ 2 anions arranged in one-dimensional chains along the b axis. Early studies 85 showed that the ground-state symmetry was s wave and the basal-plane magnetic penetration depth was in the range 5100-9800 Å.…”

Section: Organic Superconductorsmentioning

confidence: 99%

Nature of high-temperature superconductivity

Dow

Harshman

2006

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Evidence is presented that the superconducting hole condensate generally does not reside in the cuprate planes of high-temperature superconductors, but in the SrO layers, in the BaO layers, or in the regions of interstitial oxygen. Evidence that electrons, not holes, transfer to the cuprate planes of HgBa2Can−1CunO2+n+δ as a function of pressure, number n of layers, and increasing Tc is presented; holes transfer to the BaO layers. The hole transfer in YBa2Cu3O7 is also to the BaO layers. PrBa2Cu3O7 superconducts (as predicted) when it is free of pair-breaking PrBa defects in its BaO layers. The chosen locus of the superconductivity is consistent with the observation of magnetism in both the CuO layers and the cuprate planes of YBa2Cu3O7. Four materials were successfully predicted to superconduct by assuming that the cuprate planes are normal. There are no n-type high-temperature superconductors; Nd2−zCezCuO4 is p type and doped with interstitial oxygen. When Y+3 is replaced by Am+4, Pb2Sr2YCu3O8 becomes n type and stops superconducting. Holes remain near interstitial oxygen in Tl2Ba2Can−1CunO2n+4+δ. Gd2−zCezCuO4, unlike Nd2−zCezCuO4, does not superconduct because Gd has L=0 and J≠0 and breaks Cooper pairs associated with its interstitial oxygen, but Gd2−zCezSr2Cu2NbO10 does superconduct (in its SrO layers). YBa2Cu3O7 exhibits bulk nodeless (s-wave) superconductivity. We argue that the superconductivity of YBa2Cu3O7 is representative of high-Tc superconductors. The pairing mechanism is electronic (not phononic) and associated with holes on certain oxygen ions (or sulfur ions, in the case of some organic superconductors). We explore a Bardeen-Cooper-Schrieffer-type formalism applied to cuprates, ruthenates, and other compounds.

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Magnetic penetration depth and fluxon-line dynamics in the organic superconductor κ-[BEDT-TTF]2Cu[NCS]2

Cited by 46 publications

References 55 publications

Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

BaO PLANES, NOT CuO₂ PLANES, CONTAIN HIGH-T_C SUPERCONDUCTIVITY

Nature of high-temperature superconductivity

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Magnetic penetration depth and fluxon-line dynamics in the organic superconductor κ-[BEDT-TTF]2Cu[NCS]2

Cited by 46 publications

References 55 publications

Concerning the superconducting gap symmetry in YBa2Cu3O7 − δ, YBa2Cu4O8, and La2 −xSrxCuO4determined from muon spin rotation in mixed states of crystals and powders

Concerning the superconducting gap symmetry in YBa2Cu3O7 − δ, YBa2Cu4O8, and La2 −xSrxCuO4determined from muon spin rotation in mixed states of crystals and powders

BaO PLANES, NOT CuO2 PLANES, CONTAIN HIGH-TC SUPERCONDUCTIVITY

Nature of high-temperature superconductivity

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Product

Resources

About

Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

Concerning the superconducting gap symmetry in YBa₂Cu₃O_{7 − δ}, YBa₂Cu₄O₈, and La_{2 −x}Sr_xCuO₄determined from muon spin rotation in mixed states of crystals and powders

BaO PLANES, NOT CuO₂ PLANES, CONTAIN HIGH-T_C SUPERCONDUCTIVITY