Discommensuration patterns in the BiSrCaCuO high Tc superconductors

Clin, M.; Boussiri, K. El; Henocque, J.; Schneck, J.; Tolédano, J. C.; Portemer, F.; Morin, D.

doi:10.1016/s0921-4534(97)00153-6

Cited by 2 publications

(3 citation statements)

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“…This mismatch phenomenon leads to the appearance of structural discommensurations (dcs), representing fairly sharp strain-induced phase slippage in an incommensurate mass-density wave. Such behaviour has been imaged directly for BSCCO through areal contrast in dark-field electron microscopy [36]. The images are analogous to those from the Fermi-surface-controlled, incommensurate, chargedensity-wave-bearing, group Vb layer dichalcogenides [31,37].…”

Section: Diffraction Periodicities Exafs and Site-type Populationsmentioning

confidence: 99%

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

Wilson¹

1998

J. Phys.: Condens. Matter

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The subject of mixed-valence charge segregation in HTSC materials is further examined. The self-organized microstructural details are explored including 1D/2D crossover. Neutron and extended x-ray absorption fine-structure results provide the basis for this analysis. The Jahn-Teller effect is seen as a crucial element in the `charge/spin'-separation structuring. On cooling, the emergent resonating-valence-bond-type magnetic organization of the divalent subsystem assists greatly in preparing (if not pre-pairing) the overall system for high-temperature superconductivity. Under the action of the negative-U centres of the high-valence subsystem established in the domain boundaries, the system can evolve naturally with doping and cooling from towards greater s-wave-type content of the HTSC order parameter.

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Section: Diffraction Periodicities Exafs and Site-type Populationsmentioning

confidence: 99%

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

Wilson¹

1998

J. Phys.: Condens. Matter

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“…Discommensuration is a phenomenon in which the phase and/or amplitude of modulation change abruptly. Several instances of discommensuration have been reported, for example, incommensurately modulated K 2 SeO 4 and Rb 2 ZnCl 4 compounds, , charge density waves in o -TaO 3 , and Bi–Sr–Ca–Cu–O superconductors …”

Section: Discussionmentioning

confidence: 99%

“…Several instances of discommensuration have been reported, for example, incommensurately modulated K 2 SeO 4 and Rb 2 ZnCl 4 compounds, 23,60 charge density waves in o-TaO 3 , 61 and Bi−Sr−Ca−Cu−O superconductors. 62 The crystal can thus be considered a composite of the 3 × 3 square cell domains separated by the discommensuration zone within the scope of superspace methodology employed for the present X-ray data. This picture corresponds well to the domains in the γ phase observed by ABF-STEM, as shown in Figure 12.…”

Section: Structural Refinement Of γmentioning

confidence: 99%

Structural Evolution of GdBaCo₂O_5+δ (δ = 7/18) at Elevated Temperatures

et al. 2014

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The structural chemistry of the double-layered perovskite-type gadolinium barium cobaltate, GdBaCo2O5+δ (0 < δ < 1/2), is not well-known, in comparison to the representative end-member phases α at δ = 0 and β at δ = 1/2. This study unveils the structural evolution of the room-temperature stable phase γ at δ = 7/18, using in situ single-crystal X-ray diffraction at elevated temperatures and electron microscopy. The γ phase is essentially charge-ordered with Co3+ and Co2+ in a ratio of 8:1 and is incommensurately modulated in the five-dimensional superspace. The approximant of the modulated structure reveals the presence of island-like charge-ordered square cell domains interleaved with a discommensurate zone. The γ phase underwent a reversible first-order phase transition at ∼380 K to the commensurate phase β, without any change in composition at δ = 7/18. The charge ordering of Co in γ ceased in β, in combination with a redistribution of oxygen atoms (O3) in the [GdOδ] layer and a change in the spin state of Co. Further heating of β induced partial oxygen detachment at ∼700 K, causing a change in δ from 7/18 (∼0.389) to 0.19 in the nitrogen flow atmosphere. The crystal irreversibly turned into a tetragonal prototypal phase α. A peristaltic oxygen transport mechanism in GdBaCo2O5+δ (0 ≤ δ ≤ 1/2) accompanied by electron transfer and resulting in polaronic local structure relaxation is also proposed. This mechanism underpins a usefulness of the compound for application to solid oxide fuel cells as revealed in recent years.

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Discommensuration patterns in the BiSrCaCuO high Tc superconductors

Cited by 2 publications

References 20 publications

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

Structural Evolution of GdBaCo₂O_5+δ (δ = 7/18) at Elevated Temperatures

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Discommensuration patterns in the BiSrCaCuO high Tc superconductors

Cited by 2 publications

References 20 publications

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

The position of the `one-eighth' anomaly within the high-temperature superconductivity problem: matters concerning stripes and domains, Jahn-Teller effect and negative-Ubehaviour

Structural Evolution of GdBaCo2O5+δ (δ = 7/18) at Elevated Temperatures

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Structural Evolution of GdBaCo₂O_5+δ (δ = 7/18) at Elevated Temperatures