Copper spin-spin NMR relaxation in YBCO and a comparison between NMR and inelastic neutron scattering

Gillet, J.A.; Auler, T.; Horvatić, M.; Berthier, C.; Berthier, Y.; Ségransan, P.; Henry, J.Y.

doi:10.1016/0921-4534(94)92055-9

Cited by 8 publications

(3 citation statements)

References 8 publications

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“…This point can be clarified by q χ (q, ω)/ω (in 10 6 cm −3 s −1 ), with [χ (q, ω)/ω] ω→0 = χ(q, 0)/ q (equation ( 30) in the text), having assumed for χ(q, 0) and q the q-dependence as in the model by Millis et al (1990) using T 2G data since the spin-spin relaxation rate for 63 Cu(2) is related to the q-integrated χ(q, 0) (equation ( 32)). In general it is observed that below T * , 1/T 2G stays practically constant, thus supporting the interpretation in terms of frequency transfer (see for instance the experimental results of Gillet et al (1994), Takigawa (1994) and Corey et al (1996), Auler et al (1997)). On the other hand, below T 0 , 17 O and 89 Y W/T are proportional to K s , suggesting that a decrease in the amplitude of the spin fluctuations at q = 0 is involved.…”

Section: Overview Of the Main Results Of The Nmr-nqr Studiessupporting

confidence: 83%

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

1998

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After a mention of the structural, magnetic and electronic properties of high-temperature superconductors (HTSC), the basic principles of NMR-NQR experiments in these compounds are presented, emphasizing the marked differences and the novel aspects of the latter systems in comparison with metals and conventional superconductors. It follows a review of NMR-NQR spectra and relaxation rates in two-dimensional quantum antiferromagnets (particularly La 2 CuO 4 ) driven towards the superconducting state by charge doping. The main results obtained in the normal state of HTSC are summarized, while the problems of the spin-gap and of the superconducting fluctuations are discussed to a certain extent, by including the most recent contributions. An overview is given on the main conclusions derived from NMR-NQR experiments in the superconducting state. A section is devoted to the insights into the vortex lattice and the flux lines motion that have been obtained from NMR line narrowing, T 1 and echo dephasing. This review deals mostly with three systems, La 2−x Sr x CuO 4 , YBa 2 Cu 3 O 6+x and YBa 2 Cu 4 O 8 .

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Section: Overview Of the Main Results Of The Nmr-nqr Studiessupporting

confidence: 83%

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

1998

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“…17 In the Tϭ4.2 K spectrum shown in Fig. 2 one can also see an unexpected difference between the two copper isotopes: the NMR lines corresponding to the more abundant 63 Cu isotope ͑69.1%͒ are much wider than those corresponding to 65 Cu, and their line shape presents distinct oscillations which are not an experimental artifact.…”

Section: (T 2gmentioning

confidence: 83%

63,65Cu NMR investigation ofCuGeO
Fagot‐Revurat
¹
,
Horvatic-acute
²
,
Berthier
³

et al. 1997
Phys. Rev. B
Self Cite
29
4
15
0
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We report a Cu NMR study performed under high magnetic field on single crystals of the inorganic spin-Peierls CuGeO 3 compound, in its uniform and dimerized phases. The temperature (T) dependence of the magnetic hyperfine shift, i.e., the local static spin susceptibility, is found to scale the macroscopic susceptibility. This allows the determination of the hyperfine coupling tensor, which can be well accounted for by the on-site coupling associated with the localized electronic spin of a Cu ϩϩ ion in an approximately axially symmetric environment. The nuclear spin-lattice relaxation rate ͑T 1 Ϫ1 ͒ in the dimerized phase is found to be activated for temperature below ϳT SP /2. The magnetic-field dependence of the activation energy is in good agreement with that of the energy gap determined by neutron inelastic scattering. In the uniform phase, neither the magnitude of T 1 Ϫ1 ͑an order of magnitude smaller͒ nor its T dependence ͑approximately linear in T instead of being nearly constant͒ correspond to the theoretical predictions for a simple Sϭ1/2, one-dimensional Heisenberg antiferromagnet, unless we admit for a filtering of the antiferromagnetic fluctuations, due to a small supertransferred hyperfine coupling. As expected, we found no magnetic-field dependence of T 1 ͑Tտ1.5 T SP ͒ in the range 8.9-14.9 T.

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“…This is precisely the case for YBCO compounds, where the spin-spin relaxation is dominated by a temperature-dependent indirect coupling, in which one is interested because it is related to the static spin susceptibility, χ (q, ω ∼ 0). The aim of the T 2 -measurements is then to extract the spin-spin relaxation time and relate it to χ (q, ω ∼ 0), which is the physical information of interest [16].…”

Section: The Planar Copper In Yba 2 Cu 3 O 6+xmentioning

confidence: 99%

A fictitious-spin calculation of the nuclear magnetic relaxation of nuclei of spin I= 3/2 in the presence of strong quadrupole coupling

Auler

Butaud²,

Gillet

1996

J. Phys.: Condens. Matter

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The problem of the nuclear relaxation of nuclei of spin I = 3/2 in the presence of strong quadrupole coupling is treated by means of the fictitious-spin (FS) formalism. Considering the magnetic hyperfine field as the only source of spin - lattice relaxation, we employed the FS method to obtain both the multiexponential decay law of the spin - lattice relaxation and the so-called -contribution to the transverse relaxation . As an example we discuss the determination of the spin - spin relaxation rate of the planar copper in the high-temperature superconductor.

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Copper spin-spin NMR relaxation in YBCO and a comparison between NMR and inelastic neutron scattering

Cited by 8 publications

References 8 publications

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

63,65Cu NMR investigation ofCuGeO
Fagot‐Revurat
¹
,
Horvatic-acute
²
,
Berthier
³

et al. 1997
Phys. Rev. B
Self Cite
29
4
15
0
View full text Add to dashboard Cite

A fictitious-spin calculation of the nuclear magnetic relaxation of nuclei of spin I= 3/2 in the presence of strong quadrupole coupling

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Copper spin-spin NMR relaxation in YBCO and a comparison between NMR and inelastic neutron scattering

Cited by 8 publications

References 8 publications

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors

63,65Cu NMR investigation ofCuGeOFagot‐Revurat1, Horvatic-acute2, Berthier3 et al. 1997Phys. Rev. BSelf Cite294150View full textAdd to dashboardCite

A fictitious-spin calculation of the nuclear magnetic relaxation of nuclei of spin I= 3/2 in the presence of strong quadrupole coupling

Contact Info

Product

Resources

About

63,65Cu NMR investigation ofCuGeO
Fagot‐Revurat
¹
,
Horvatic-acute
²
,
Berthier
³

et al. 1997
Phys. Rev. B
Self Cite
29
4
15
0
View full text Add to dashboard Cite