Magnetic order and superconductivity in La2$minus;xSrxCuO4: a review

Julien, M.-H.

doi:10.1016/s0921-4526(02)01997-x

Cited by 103 publications

(113 citation statements)

References 48 publications

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“…In this context, we also note the similarities with the phase diagram of the cuprate HTSCs, where a comparable coexistence of magnetic correlations and superconductivity has been established [14][15][16] . Indeed, strongly disordered static magnetism also coexists with superconductivity in the so-called strongly underdoped regime.…”

supporting

confidence: 61%

“…A particularly important question is how magnetism and superconductivity evolve on electron doping. In this context, muon spin rotation (μSR) is an ideal technique as it provides microscopic information corresponding to the bulk of a sample and there is a substantial body of μSR data that has been collected on the copper-oxide HTSCs for comparison [14][15][16] .Here, we present our zero-field μSR (ZF-μSR) measurements, which detail how magnetism evolves with F doping from the SDW state below T mag ≈ 135 K in the parent compound at x = 0 towards the superconducting state at x 0.1. In particular, we show that static magnetic correlations originating from the FeAs layers survive to a surprisingly high doping level well into the superconducting regime.…”

mentioning

confidence: 99%

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Coexistence of static magnetism and superconductivity in SmFeAsO1−xFx as revealed by muon spin rotation

et al. 2009

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The recent observation of superconductivity with critical temperatures (T c ) up to 55 K in the pnictide RFeAsO 1−x F x , where R is a lanthanide, marks the first discovery of a noncopper-oxide-based layered high-T c superconductor 1-3 . It has raised the suspicion that these new materials share a similar pairing mechanism to the cuprate superconductors, as both families exhibit superconductivity following charge doping of a magnetic parent material. In this context, it is important to follow the evolution of the microscopic magnetic properties of the pnictides with doping and hence to determine whether magnetic correlations coexist with superconductivity. Here, we present a muon spin rotation study on SmFeAsO 1−x F x , with x = 0-0.30 that shows that, as in the cuprates, static magnetism persists well into the superconducting regime. This analogy is quite surprising as the parent compounds of the two families have rather different magnetic ground states: itinerant spin density wave for the pnictides contrasted with the MottHubbard insulator in the cuprates. Our findings therefore suggest that the proximity to magnetic order and associated soft magnetic fluctuations, rather than strong electronic correlations in the vicinity of a Mott-Hubbard transition, may be the key ingredients of high-T c superconductors.Similar to the cuprates, the pnictide high-critical-temperature (T c ) superconductors (HTSCs) have a layered structure comprising alternating FeAs and LaO sheets, with the Fe arranged on a square lattice 1 . Theoretical calculations predict a quasi-twodimensional electronic structure, with LaO layers that mainly act as blocking layers and metallic FeAs layers that are responsible for superconductivity [4][5][6] , although these are multiband superconductors with up to five FeAs-related bands crossing the Fermi level [4][5][6][7] . Like the copper-oxide HTSCs, the superconducting state in the pnictides emerges on charge doping a magnetic parent compound [8][9][10] , with indications that the maximal T c occurs just as magnetism disappears [11][12][13] . The last point may well be of great significance, as the parent compounds in the two families are very different. For the pnictides, there are strong indications that they are itinerant systems with magnetism arising from a nesting-induced spin density wave (SDW). This is in contrast to the cuprates, where it is well established that the mother compounds are 'charge transfer insulators', where strongly repulsive electronic correlations yield an insulating and antiferromagnetic ground state despite a half-filled conduction band. It is therefore of great importance to obtain further insight into the differences and similarities of the pnictide and cuprate HTSCs. A particularly important question is how magnetism and superconductivity evolve on electron doping. In this context, muon spin rotation (μSR) is an ideal technique as it provides microscopic information corresponding to the bulk of a sample and there is a substantial body of μSR data that has been colle...

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confidence: 61%

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confidence: 99%

mentioning

confidence: 99%

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Coexistence of static magnetism and superconductivity in SmFeAsO1−xFx as revealed by muon spin rotation

et al. 2009

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“…20 The peak in the freezing temperature is associated with an increased competition between static magnetic order and superconductivity and a decrease of T c . 16 We have argued that for p = 0.12, the spin-frozen low-temperature state permits an anisotropy gap akin to that observed in the parent insulator La 2 CuO 4 .…”

Section: B Anisotropy Gapmentioning

confidence: 99%

“…For LSCO the freezing temperature T f , derived from local probes such as NMR, NQR and muon spin rotation (μSR) has a narrow peak centered around x max ∼ 0.12. 20 It appears reasonable to conjecture that the details of the magnetic excitation spectrum may be highly sensitive to doping near x max . The available experimental evidence is, however, limited and a consistent interpretation is lacking.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2013

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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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