Suppression of the Superconducting Condensate in the High-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">T</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>Cuprates by Zn Substitution and Overdoping: Evidence for an Unconventional Pairing State

Bernhard, C.; Tallon, J. L.; Bucci, C.; Renzi, R. De; Guidi, G.; Williams, G. V. M.; Niedermayer, Ch.

doi:10.1103/physrevlett.77.2304

Cited by 145 publications

(112 citation statements)

References 30 publications

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“…In particular, both the strong-coupling d-wave model in the unitarity limit and the ''swiss cheese'' model predict T c Ӷ10 K when 1/ 2 Ϸ0.3 m Ϫ2 ͓i.e., Ϸ0.02 s Ϫ1 in a muon spin resonance ( SR) measurement͔. 10,23 It is, therefore, interesting to note that all of our data points fall on the far left of this line. In particular, the T c of sample C2 with 1/ 2 Ϸ0.3 m Ϫ2 is still 15 K or higher.…”

mentioning

confidence: 82%

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
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The hole concentration p(␦), the transition temperature T c , the intragrain penetration depth , and the Meissner effect were measured for annealed RuSr 2 (Gd,Ce) 2 Cu 2 O 10ϩ␦ samples. The intragrain superconducting transition temperature T c varied from 17 to 40 K while the p changed by only 0.03 holes/CuO 2 . The intragrain superfluid density 1/ 2 and the diamagnetic drop of the field-cooled magnetization across T c ͑the Meissner effect͒, however, increased more than 10 times. All of these findings are in disagreement with both the T c vs p and the T c vs 1/ 2 correlations proposed for homogeneous cuprates, but are in line with a possible phase separation and the granularity associated with it. underdoped nature ͑i.e., the hole concentration pӶ0.16 holes/CuO 2 ) or the competition between the SC and the coexisting FM through the Fulde-FerrellLarkin-Ovchinnikov ͑FFLO͒ phase. 1-5 A verification was difficult until the recent reports that the transition temperatures T c of Ru1222 and Ru1212 can be adjusted over a broad range by oxygen annealing and Cu substitution, respectively. [6][7][8] The reported data, unfortunately, show that the T c enhancement is accompanied by both a p increase and a suppression of the ferromagnetic spin order and offer no clear distinction. To explore the topic, we measured the intragrain T c , the p, the intragrain superfluid density 1/ 2 , and the Meissner effect in several annealed Ru1222 samples. The data were then compared with both the T c vs p correlation 9 and the T c vs 1/ 2 line proposed. 10 We observed that a twofold enhancement of T c ͑from 17 to 40 K͒ is accompanied by a relatively small change of p ͑from 0.09 to 0.12 holes/CuO 2 ), but a 20-fold increase in 1/ 2 ͑from 0.3 to 6 m Ϫ2 ). Together with an extremely large field effect of dT c /dHϾ100 K/T and a linear increase of the Meissner fraction with 1/ 2 , the data suggest that those ruthenocuprate grains are actually Josephson-junction arrays ͑JJA's͒, in agreement with the phase-separation model suggested. 11 Further investigations of local magnetic structures are needed to solve the problem.Ceramic RuSr 2 (Gd 0.7 Ce 0.3 ) 2 Cu 2 O 10ϩ␦ samples were synthesized following the standard solid-state-reaction procedure. Precursors were first prepared by calcined commercial oxides at 400-900°C under flowing O 2 . Mixed powder with a proper cation ratio was then pressed into pellets and sintered at 900°C in air for 24 h. The final heat treatment of the ceramics was done at 1090°C for 60 h after repeatedly sintering and regrinding at 1000°C. Powders with different particle sizes were prepared according to the procedures previously reported. 12 The structure of the samples was determined by powder x-ray diffraction ͑XRD͒, using a Rigaku DMAX-IIIB diffractometer. The XRD pattern of a typical sample is shown in Fig. 1. Refinement was done based on a space group of I4/mmm with lattice parameters of aϭ3.839(1) and cϭ28.591(5) using the RIETAN-2000 program. 13 There are no noticeable impurity lines in the x-ray diffraction pattern ...

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mentioning

confidence: 82%

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
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“…This impurity averaging technique was first used by Abrikosov and Gorkov 14 for conventional s-wave superconductors. Recent experimental measurements by Bernhard et al 17 on various types of YBa 2 (Cu 1−x Zn x ) 3 O 7−δ samples have shown that the depression of T c by Zn doping can be fitted well with the Abrikosov-Gorkov theory applied to the d-wave superconductivity. Now we give a derivation for the gap function from T ǫn≥0 F †(R) (ǫ n + ω, ǫ n ).…”

Section: B Normal Partmentioning

confidence: 90%

Time-dependent Ginzburg-Landau equations for mixedd−ands-wave superconductors

et al. 1998

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A set of coupled time-dependent Ginzburg-Landau equations (TDGL) for superconductors of mixed d-and s-wave symmetry are derived microscopically from the Gor'kov equations by using the analytical continuation technique. The scattering effects due to impurities with both nonmagnetic and magnetic interactions are considered. We find that the d-and s-wave components of the order parameter can have very different relaxation times in the presence of nonmagnetic impurities. This result is contrary to a set of phenomenologically proposed TDGL equations and thus may lead to new physics in the dynamics of flux motion.

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“…Clearly, atomic-layer-by-layer synthesis capability has been critical for this task. Zn was chosen because it is known to suppress T c and the superfluid carrier density n s significantly, without affecting the carrier density [15][16][17][18] The results obtained in the experiment with M-I bilayers are summarized in figure 6: T c remained unchanged at approximately 30 K in almost all the films. The only exceptions were those in which Zn d-doping was carried out in the second CuO 2 plane counting from the nominal geometric M-I interface towards the surface of the sample (N = 2), in which case a drop to T c ≈ 18 K was observed.…”

Section: Interface Superconductivitymentioning

confidence: 99%

Insights from the study of high-temperature interface superconductivity

Pereiro

Bollinger

Логвенов

et al. 2012

Phil. Trans. R. Soc. A.

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A brief overview is given of the studies of high-temperature interface superconductivity based on atomic-layer-by-layer molecular beam epitaxy (ALL-MBE). A number of difficult materials science and physics questions have been tackled, frequently at the expense of some technical tour de force, and sometimes even by introducing new techniques. ALL-MBE is especially suitable to address questions related to surface and interface physics. Using this technique, it has been demonstrated that high-temperature superconductivity can occur in a single copper oxide layer-the thinnest superconductor known. It has been shown that interface superconductivity in cuprates is a genuine electronic effect-it arises from charge transfer (electron depletion and accumulation) across the interface driven by the difference in chemical potentials rather than from cation diffusion and mixing. We have also understood the nature of the superconductorinsulator phase transition as a function of doping. However, a few important questions, such as the mechanism of interfacial enhancement of the critical temperature, are still outstanding.

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Suppression of the Superconducting Condensate in the High-TcCuprates by Zn Substitution and Overdoping: Evidence for an Unconventional Pairing State

Cited by 145 publications

References 30 publications

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
View full text Add to dashboard Cite

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
View full text Add to dashboard Cite

Time-dependent Ginzburg-Landau equations for mixedd−ands-wave superconductors

Insights from the study of high-temperature interface superconductivity

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Suppression of the Superconducting Condensate in the High-TcCuprates by Zn Substitution and Overdoping: Evidence for an Unconventional Pairing State

Cited by 145 publications

References 30 publications

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2Xue1, Lorenz2, Baikalov3 et al. 2002Phys. Rev. B283331View full textAdd to dashboardCite

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2Xue1, Lorenz2, Baikalov3 et al. 2002Phys. Rev. B283331View full textAdd to dashboardCite

Time-dependent Ginzburg-Landau equations for mixedd−ands-wave superconductors

Insights from the study of high-temperature interface superconductivity

Contact Info

Product

Resources

About

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
View full text Add to dashboard Cite

Superconductivity, intragrain penetration depth, and Meissner effect ofRuSr2(Gd,Ce)2
Xue
¹
,
Lorenz
²
,
Baikalov
³

et al. 2002
Phys. Rev. B
28
3
33
1
View full text Add to dashboard Cite