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Beck, Roy; Kohen, A.; Leibovitch, G.; Castro, H.; Deutscher, G.

doi:10.1023/a:1022986816430

Cited by 3 publications

(8 citation statements)

References 4 publications

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“…2c. This is in agreement with measurements performed earlier on thick films in decreasing fields [15,20] and confirms the assumption that Meissner currents are weak in that case, but may be not negligible in view of the smaller slope obtained here.…”

supporting

confidence: 94%

“…This highly hysteretic behavior has been ascribed to strong screening currents in increasing fields and much weaker ones in decreasing fields as discussed above. [15,20]. The negligible hysteresis observed in our thin samples implies that the screening currents are very low even in increasing fields and that the two finite bias peaks cannot be due to a Doppler shift of the zero energy bound states.…”

mentioning

confidence: 66%

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Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

et al. 2007

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We have probed the Landau levels of nodal quasi-particles by tunneling along a nodal direction of (110) oriented YBa2Cu3O7−x thin films with a magnetic field applied perpendicular to the CuO2 planes, and parallel to the film's surface. In optimally doped films and at low temperature, finite energy nodal states are clearly observed in films thinner than the London penetration depth. Above a well defined temperature the order parameter reverts to a pure d -wave symmetry.

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supporting

confidence: 94%

mentioning

confidence: 66%

Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

et al. 2007

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“…Later results, obtained on films that did have the (110) orientation, show a more complex behavior. In particular there is a strong splitting in decreasing fields, and it persists even at small thickness (Beck et al, 2003;Dagan and Deutscher, 2001b). This behavior raises questions that will be discussed in the last section of this review.…”

Section: High Z (110) Contacts Under Magnetic Fieldsmentioning

confidence: 98%

“…In this model, the competing order parameter dominates over the superconducting one only in the anti-node regions. Specifically the origin of the pseudogap lies in the vicinity of a Charge Density Wave (CDW) (Benfatto et al, 2000) line T * (p) , as mentioned above, but from a phenomenological standpoint their main results are given in terms of a gap ∆(φ) which is dominated by the pseudogap ∆ p near the anti-nodal points and by the superconducting order parameter near the nodes. They argue in favor of the weak coupling limit ∆ < t, where t is the nearest neighbor interaction term in the tight binding approximation, so that T c is equal within a numerical factor to the energy scale that governs the behavior of ∆ near the nodes.…”

Section: Two Gap Modelmentioning

confidence: 99%

“…Beck et al (Beck et al, 2004) have remarked that the current effect should cancel out in decreasing fields, because it is known that there is no Bean-Livingston surface barrier against flux exit. A ZBCP split in decreasing fields, if observed, should therefore be primarily a field effect, and not a current effect.…”

Section: A Asj Bound States Under Applied Fieldsmentioning

confidence: 99%

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Andreev–Saint-James reflections: A probe of cuprate superconductors

2005

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Electrical transport through a normal metal / superconductor contact at biases smaller than the energy gap can occur via the reflection of an electron as a hole of opposite wave vector. The same mechanism of electron-hole reflection gives rise to low energy states at the surface of unconventional superconductors having nodes in their order parameter. The occurrence of electron-hole reflections at normal metal / superconductor interfaces was predicted independently by Saint James and de Gennes and by Andreev, and their spectroscopic features discussed in detail by Saint James in the early sixties. They are generally called Andreev reflections but, for that reason, we call them Andreev -Saint James (ASJ) reflections. We present a historical review of ASJ reflections and spectroscopy in conventional superconductors, and review their application to the High Tc cuprates. The occurrence of ASJ reflections in all studied cuprates is well documented for a broad range of doping levels, implying that there is no large asymmetry between electrons and holes near the Fermi level in the superconducting state. In the underdoped regime, where the pseudo-gap phenomenon has been observed by other methods such as NMR, ARPES and Giaever tunneling, gap values obtained from ASJ spectroscopy are smaller than pseudo-gap values, indicating a lack of coherence in the pseudo-gap energy range. Low energy surface bound states have been observed in all studied hole doped cuprates, in agreement with a dominant d-wave symmetry order parameter. Results are mixed for electron doped cuprates. In overdoped Y Ba 2 Cu 3 O 7−δ (δ < 0.08) and La 2−x SrxCuO 4 , ASJ spectroscopy is consistent with the presence of an additional imaginary component of the order parameter. Results of ASJ spectroscopy under applied magnetic fields are also reviewed. A short section at the end is devoted to some recent results on spin effects. * Electronic address: guyde@tau.ac.il 2

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High quality a-axis outgrowth on c-axis Y_1 xCa_xBa₂Cu₃O₇

Leibovitch¹,

Beck²,

Deutscher³

2004

Supercond. Sci. Technol.

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The large amplitude of the high Tc (HTSC) superconducting gap is attractive for improved electronic applications. However, the study of such HTSC cuprates has uncovered that unlike the s-wave order parameter of the low Tc superconductors (LTSC), an angle dependent dx2−y2 wavefunction is the dominant order parameter in such compounds. This symmetry causes low energy surface bound states, detrimental for applications, except at (100) oriented surfaces. It is therefore essential to have a smooth and well oriented surface of the crystallographic a-axis (100). In this work we present a study of an unconventional way to attain such surfaces in the form of a-axis outgrowth on a c-axis surface of sputtered Y1−xCaxBa2Cu3O7−δ thin film. The grain topography was tested using x-ray, SEM and AFM together with point contact and tunnel junctions measurements.

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Cited by 3 publications

References 4 publications

Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

Andreev–Saint-James reflections: A probe of cuprate superconductors

High quality a-axis outgrowth on c-axis Y_1 xCa_xBa₂Cu₃O₇

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Untitled

Cited by 3 publications

References 4 publications

Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

Transition from a Mixed to a Pured-Wave Symmetry in Superconducting Optimally DopedYBa2Cu3O7−x

Andreev–Saint-James reflections: A probe of cuprate superconductors

High quality a-axis outgrowth on c-axis Y1 xCaxBa2Cu3O7

Contact Info

Product

Resources

About

High quality a-axis outgrowth on c-axis Y_1 xCa_xBa₂Cu₃O₇