Stripe Correlations Of Spins Research Articles

Possible Existence of the Stripe Correlations in Electron-Doped Superconducting Cuprates Eu<sub>1.85</sub>Ce<sub>0.15</sub>Cu<sub>1-y</sub>Ni<sub>y</sub>O<sub>4+α-δ</sub> Studied by Muon-Spin-Relaxation

Partially Ni-substituted electron-doped superconducting cuprates of Eu1.85Ce0.15Cu1-yNiyO4+α-δ (ECCNO) with y = 0, 0.01, 0.02 and 0.05 have been studied by muon-spin-relaxation (mSR) measurements, in order to elucidate whether or not the dynamical stripe correlations of spins and charges exist in electron-doped cuprates. It has been found that the development of the Cu-spin correlation is induced at low temperatures through the Ni substitution and that, for y = 0.02, a muon-spin precession due to a long-range magnetic order has been observed at 10 K. These results suggest a possibility that the stripe model can globally explain the high-Tc superconductivity in both hole- and electron-doped cuprates.

μSR study of effects of rare-earth moments on the 1/8 anomaly in the excess-oxygen-doped high- Tc cuprates La 2− xA xCuO 4+ δ (A = Eu, Pr)

In the zero-field muon-spin-relaxation measurements of the excess-oxygen-doped La 2− x (Eu, Pr) x CuO 4+ δ , a muon-spin precession corresponding to the formation of a long-range magnetic order of Cu spins has been observed around δ = 0.0625 (the hole concentration per Cu, p = 2 δ = 1/8) in the nonmagnetic-Eu-substituted system and around δ = 0.082 in the Pr-substituted system, respectively, where the superconductivity is slightly suppressed in both systems. In the Pr-substituted system, it appears that p is effectively ∼1/8 in the CuO 2 plane around δ = 0.082, owing to the hybridization between Pr 4f and O 2p orbitals. These results are similar to that previously observed in the magnetic-Nd-substituted La 1.8Nd 0.2CuO 4+ δ . It is concluded that the 1/8 anomaly and the stripe correlations of spins and holes exist inherently in the excess-oxygen-doped La-214 systems independent of rare-earth moments.

Stripe correlations of spins and holes in cuprate superconductors

It is argued that the stripe order of spins and holes found in La2−xSrxNiO4+δ is a useful model for spin and charge correlations in La2−xSrxCuO4. A direct connection with the cuprates is now established by neutron diffraction evidence for stripe order in La1.6−xNd0.4SrxCuO4 withx=0.12. The experimental work has stimulated new theoretical ideas.

Stripe correlations of spins and holes in cuprates and nickelates

Recent neutron diffraction studies of coupled spatial modulations of the spin and charge densities within the CuO2 planes of layered cuprates (and NiO2 planes of nickelate analogs) are reviewed. Analysis of superlattice peaks that appear at low temperatures (≤ 100 K) in hole-doped La2NiO4 indicates that the holes tend to localize in periodically-ordered antiphase domain walls separating antiferromagnetic stripes of Ni spins. Evidence for a similar ordering has now been found in a copper-oxide compound. La1.6-xNd0.4SrxCuO4 with ≈ 1/8, in which the superconductivity is anomalously suppressed. It is proposed that dynamical correlations of the same nature occur in superconducting cuprates. The relevance to the low-energy electrodynamics is discussed.

Stripe correlations of spins and holes in copper oxide superconductors

Abstract Neutron scattering has played a crucial role in elucidating the phase diagram of the prototypical high-tem-perature superconductor La2-xSrxCuO4 (see Figure 1). The commensurate antiferromagnetic order that is present in the undoped compound is destroyed by a hole concentration (given by x) of 0.02 [l]. At higher hole concentrations (x > 0.05), where high-temperature superconductivity occurs, dynamical two-dimensional spin correlations characterized by an incommensurate wave vector (see Figure 2a) have been detected [2–4]. Further studies have clarified the momentum, energy and temperature dependencies of these excitations [5–8]; nevertheless, their underlying nature and the cause of the incommensurability have not been firmly established.