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We present high-resolution triple-axis neutron scattering studies of the high-temperature superconductor La 1.88 Sr 0.12 CuO 4 (T c = 27 K). The temperature dependence of the low-energy incommensurate magnetic fluctuations reveals distinctly glassy features. The glassiness is confirmed by the difference between the ordering temperature T N T c inferred from elastic neutron scattering and the freezing temperature T f 11 K obtained from muon spin rotation studies. The magnetic field independence of the observed excitation spectrum as well as the observation of a partial suppression of magnetic spectral weight below 0.75 meV for temperatures smaller than T f , indicate that the stripe frozen state is capable of supporting a spin anisotropy gap, of a magnitude similar to that observed in the spin and charge stripe-ordered ground state of La 1.875 Ba 0.125 CuO 4 . The difference between T N and T f implies that the significant enhancement in a magnetic field of nominally elastic incommensurate scattering is caused by strictly inelastic scattering-at least in the temperature range between T f and T c -which is not resolved in the present experiment. Combining the results obtained from our study of La 1.88 Sr 0.12 CuO 4 with a critical reappraisal of published neutron scattering work on samples with chemical composition close to p = 0.12, where local probes indicate a sharp maximum in T f (p), we arrive at the view that the low-energy fluctuations are strongly dependent on composition in this regime, with anisotropy gaps dominating only sufficiently close to p = 0.12 and superconducting spin gaps dominating elsewhere.

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“…17,19,21,[32][33][34] In Fig. 1(a), we show a constant energy scan obtained with the spectrometer set to energy transferhω = 0 meV.…”

Section: Resultsmentioning

confidence: 99%

Glassy low-energy spin fluctuations and anisotropy gap in La1.88Sr0.12CuO4<

et al. 2013

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“…T he enhancement of spin-stripe order by a magnetic field in [3][4][5][6][7] . Recently, the discovery of charge order in YBa 2 Cu 3 O y appearing only for fields perpendicular to the copper-oxide planes sufficiently strong to be detrimental to superconductivity 8 , as well as the subsequent observation of related charge density wave (CDW) correlations [9][10][11] , has provided further evidence of competition.…”

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confidence: 99%

Emergence of charge order from the vortex state of a high-temperature superconductor

et al. 2013

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Evidence is mounting that charge order competes with superconductivity in high T c cuprates. Whether this has any relationship to the pairing mechanism is unknown as neither the universality of the competition nor its microscopic nature has been established. Here, we show using nuclear magnetic resonance that charge order in YBa 2 Cu 3 O y has maximum strength inside the superconducting dome, similar to compounds of the La 2 À x (Sr,Ba) x CuO 4 family. In YBa 2 Cu 3 O y , this occurs at doping levels of p ¼ 0.11-0.12. We further show that the overlap of halos of incipient charge order around vortex cores, similar to those visualised in Bi 2 Sr 2 CaCu 2 O 8 þ d , can explain the threshold magnetic field at which long-range charge order emerges. These results reveal universal features of a competition in which charge order and superconductivity appear as joint instabilities of the same normal state, whose relative balance can be field-tuned in the vortex state.

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“…For an intermediate doping concentration of x = 0.144, Khaykovich et al [230] have recently shown that, although no elastic magnetic peaks are seen at zero field, a static SDW does appear for H > H c ∼ 3 T. Such behavior [224], [223], [230], [52], and [51]. The solid curve suggests the shape of a boundary between a state with spin-density-wave order and superconductivity on the left and superconductivity alone on the right, as first proposed by Demler et al [225].…”

Section: Magnetic Fieldmentioning

confidence: 99%

“…8.20. For samples with lower doping (x = 0.10 [224] and 0.12 [223]) there is a small elastic, incommensurate, magnetic peak intensity in zero field that is substantially enhanced by application of a c-axis magnetic field. The growth of the intensity with field is consistent with 13) where H c2 is the upper critical field for superconductivity [224].…”

Section: Magnetic Fieldmentioning

confidence: 99%

Neutron Scattering Studies of Antiferromagnetic Correlations in Cuprates

Tranquada

Handbook of High-Temperature Superconductivity

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Summary. Neutron scattering studies have provided important information about the momentum and energy dependence of magnetic excitations in cuprate superconductors. Of particular interest are the recent indications of a universal magnetic excitation spectrum in hole-doped cuprates. That starting point provides motivation for reviewing the antiferromagnetic state of the parent insulators, and the destruction of the ordered state by hole doping. The nature of spin correlations in stripeordered phases is discussed, followed by a description of the doping and temperature dependence of magnetic correlations in superconducting cuprates. After describing the impact on the magnetic correlations of perturbations such as an applied magnetic field or impurity substitution, a brief summary of work on electron-doped cuprates is given. The chapter concludes with a summary of experimental trends and a discussion of theoretical perspectives. IntroductionNeutron scattering has played a major role in characterizing the nature and strength of antiferromagnetic interactions and correlations in the cuprates. Following Anderson's observation [1] that La 2 CuO 4 , the parent compound of the first high-temperature superconductor, should be a correlated insulator, with moments of neighboring Cu 2+ ions anti-aligned due to the superexchange interaction, antiferromagnetic order was discovered in a neutron diffraction study of a polycrystalline sample [2]. When single-crystal samples became available, inelastic studies of the spin waves determined the strength of the superexchange, J, as well as weaker interactions, such as the coupling between CuO 2 layers. The existence of strong antiferromagnetic spin correlations above the Néel temperature, T N , has been demonstrated and explained. Over time, the quality of such characterizations has improved considerably with gradual evolution in the size and quality of samples and in experimental techniques.Of course, what we are really interested in understanding are the optimallydoped cuprate superconductors. It took much longer to get a clear picture of the magnetic excitations in these compounds, which should not be surprising

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Enhancement of static antiferromagnetic correlations by magnetic field in a superconductorLa2−xSrx

Cited by 155 publications

References 14 publications

Glassy low-energy spin fluctuations and anisotropy gap in La1.88Sr0.12CuO4<

Glassy low-energy spin fluctuations and anisotropy gap in La1.88Sr0.12CuO4<

Emergence of charge order from the vortex state of a high-temperature superconductor

Neutron Scattering Studies of Antiferromagnetic Correlations in Cuprates

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