SPIN DYNAMICS IN THE NORMAL STATE OF HIGH-T<sub><font>c</font></sub> SUPERCONDUCTORS

Si, Qimiao

doi:10.1142/s0217979294000038

Cited by 7 publications

(2 citation statements)

References 42 publications

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“…Here, the exponent a depends on the choice of the specific model. A value a 2 is predicted by the generalized marginal Fermi liquid scenario [7,17] while the nearly antiferromagnetic Fermi liquid (NAFL) scenario [7] demands a 3. As shown in Fig.…”

Section: Interplane Electronic Spin Polarizationmentioning

confidence: 99%

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
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We report a spin-echo double resonance study of the plane Cu sites in the superconducting state of nearly optimally doped Y 2 Ba 4 Cu 7 O 15 employing nuclear quadrupole resonance. The detailed analysis of the temperature dependence of the indirect in-plane and interplane spin-spin relaxation rate reveals two results: (i) In the normal conducting state, strong antiferromagnetic correlations exist between adjacent CuO 2 layers. (ii) In the superconducting state, the electronic spin polarization transfer between these layers is drastically reduced for decreasing temperature. Both findings are consistent with the interlayer tunneling model. [S0031-9007(99)08388-X] PACS numbers: 76.60. Gv, 74.20.Mn, 74.72.Bk Superconductivity in Y-Ba-Cu-O high-temperature superconductors takes place in the CuO 2 planes which form double planes (or bilayers). Experimentally, one finds that the maximum of the critical temperature, T c , of bilayer compounds is systematically higher than the one of the corresponding single layer material. This clearly indicates that the charge carrier correlation between adjacent CuO 2 layers has important implications for any kind of model that tries to explain superconductivity. The most prominent ansatz that involves explicitly the interlayer mechanism is the interlayer tunneling model by Anderson and co-workers [1]. In this model, the coherent single-particle tunneling between adjacent layers is blocked, resulting in a 2D normal state charge carrier confinement that is lifted by the superconducting transition through interlayer Josephson tunneling. As a result, this leads to an amplification of the pairing mechanism within the single layer and thus to an increased T c .Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) methods which probe the electronic system in its ground state, i.e., at frequencies close to zero, are well suited to test the interlayer tunneling model. Among the many bilayer compounds Y 2 Ba 4 Cu 7 O 15 is the ideal substance to perform such an investigation. Its structure consists of a sequence of alternating YBa 2 Cu 3 O 7 (1-2-3 for short) and YBa 2 Cu 4 O 8 (1-2-4) blocks with plane Cu sites Cu(2) and Cu(3), respectively. As in YBa 2 Cu 3 O 7 and YBa 2 Cu 4 O 8 , the CuO 2 planes in Y 2 Ba 4 Cu 7 O 15 form double planes separated by Y ions. However, because of the alternation of 1-2-3 and 1-2-4 blocks the individual planes of a CuO 2 bilayer in Y 2 Ba 4 Cu 7 O 15 are inequivalent and hence can separately be monitored by NMR and NQR methods. This can be accomplished because the plane Cu NQR lines of both blocks are quite narrow and well separated [2][3][4].In this Letter, we report on new measurements that extend our earlier NQR spin-echo double resonance (SE-DOR) experiments [2] into the superconducting (SC) state of Y 2 Ba 4 Cu 7 O 15 . We show that, in the normal conducting (NC) state with decreasing temperature, strong antifer-romagnetic correlations and an increasing electronic spin polarization transfer between the two inequivalent CuO 2 planes tak...

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Section: Interplane Electronic Spin Polarizationmentioning

confidence: 99%

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
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“…Under a more complete examination it now has become accepted that the nuclear resonance data (particularly NMR) and the neutron scattering data cannot comprehensively be rendered compatible within a homogeneous scheme that inserts solely the presumed dominance of spin-fluctuation physics [109]. Quite a few have trodden that route and been driven to backtrack to some degree [110].…”

Section: Why the Current Spin Fluctuation Interpretation Of Htsc Is N...mentioning

confidence: 99%

High- - a negative-Uinterpretation of cuprate superconductivity, incorporating questions of crossover, micro-inhomogeneity and a compound order parameter

Wilson¹,

Zahrir²

1997

Rep. Prog. Phys.

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The two-subsystem, negative-U interpretation of high-temperature superconducting (HTSC) behaviour in the mixed-valent, square-planar cuprate metals is pursued further. The question of the symmetry of the order parameter is central to understanding the HTSC phenomenon. Many have by now examined the potentialities of a mixed order parameter to cope with the wealth of data of all types available from these materials. It is emphasized here that it is actually a mistake for the present mixed-valent, highly tight-binding systems to seek a single, spatially homogeneous, compound order parameter. The systems are demonstrably micro-inhomogeneous due to charge segregation as in many substituted systems very close to Mott localization. In these circumstances there is a fascinating interplay between magnetism, charge and structural aspects to the problem at the unit cell level. Questions of local moment seeding, of local trapping of carriers structurally and magnetically, of on-site Jahn-Teller and bonding distortions, on the one hand, are highly intertwined, on the other, with somewhat more delocalized aspects to the problem, like SDWs, CDWs, the resonant valence band state, etc. All these matters have to be treated simultaneously, in a way appropriate to the precise level of carrier doping secured. Control over the outcome is dependent, moreover, from system to system upon the detailed degree of covalency introduced into the problem by the particular counter-ions employed.The present review makes an attempt to hold together all the published information on a coherent basis. That basis is seen as being provided by a negative-U sequencing of state energies in the mixed-valent cuprates, once it is accepted that the systems are not homogeneous at the micro-level. Results on the LSCO system, for example, find interpretation in terms of moderately well organized discommensurations in charge and spin distribution.The fact that this approach has been followed from the beginnings of high-temperature superconduction, now nearly ten years ago, without any sustained discouragement from the accumulating data, indicates that it provides a means of interpretation worth more direct attention than it has received to date. In particular it provides very naturally a means to understand what it is that confines high-temperature superconduction to its narrow range-the square-planar, layered, mixed-valent cuprates. There is in essence only one high-temperature superconductor and this paper attempts again to say why.

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Magnetic correlations in high temperature superconductivity

1994

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SPIN DYNAMICS IN THE NORMAL STATE OF HIGH-T_c SUPERCONDUCTORS

Cited by 7 publications

References 42 publications

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
View full text Add to dashboard Cite

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
View full text Add to dashboard Cite

High- - a negative-Uinterpretation of cuprate superconductivity, incorporating questions of crossover, micro-inhomogeneity and a compound order parameter

Magnetic correlations in high temperature superconductivity

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SPIN DYNAMICS IN THE NORMAL STATE OF HIGH-Tc SUPERCONDUCTORS

Cited by 7 publications

References 42 publications

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7Suter1, Mali2, Roos3 et al. 1999Phys. Rev. Lett.2330View full textAdd to dashboardCite

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7Suter1, Mali2, Roos3 et al. 1999Phys. Rev. Lett.2330View full textAdd to dashboardCite

High- - a negative-Uinterpretation of cuprate superconductivity, incorporating questions of crossover, micro-inhomogeneity and a compound order parameter

Magnetic correlations in high temperature superconductivity

Contact Info

Product

Resources

About

SPIN DYNAMICS IN THE NORMAL STATE OF HIGH-T_c SUPERCONDUCTORS

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
View full text Add to dashboard Cite

Interplane Electronic Spin Polarization Transfer in the Superconducting State ofY2Ba4Cu7
Suter
¹
,
Mali
²
,
Roos
³

et al. 1999
Phys. Rev. Lett.
2
3
3
0
View full text Add to dashboard Cite