The two-component physics in cuprates in the real space and in the momentum representation

Gradual evolution of two phase coexistence between dynamical and static regimes in cuprates is first investigated in the real space by making use of the available neutron scattering, NMR and mSR data. Analysis of the Hall effect and the ARPES spectra reveals the presence of two groups of charge carriers in LSCO. The T-dependent component is due to the thermal activation of bound electron-hole structures seen near antinodal points in the Brillouin zone, thus introducing the two-component physics also for the momentum representation. Interpretation of so-called "van Hove bands" undergoes drastic changes. Importance of the findings for pseudo-gap physics is stressed. Relation to some recent STM and STS results is discussed.Comment: 8 pages, 6 figures, reported at LEHTSC 2007 conference (Tsukuba), submitted to Journal of Physics: Conference Serie

Charge Segregation, Cluster Spin-Glass and Superconductivity in La1.94Sr0.06CuO4

A 63Cu and 139La NMR/NQR study of superconducting (Tc=7 K) La1.94Sr0.06CuO4 single crystal is reported. Coexistence of spin-glass and superconducting phases is found below ~5 K from 139La NMR relaxation. 63Cu and 139La NMR spectra show that, upon cooling, CuO2 planes progressively separate into two magnetic phases, one of them having enhanced antiferromagnetic correlations. These results establish the AF-cluster nature of the spin-glass. We discuss how this phase can be related to the microsegregation of mobile holes and to the possible pinning of charge-stripes.Comment: 4 pages. Modified manuscript with clarification

First time determination of the microscopic structure of a stripe phase: Low temperature NMR in La2NiO4.17

The experimental observations of stripes in superconducting cuprates and insulating nickelates clearly show the modulation in charge and spin density. However, these have proven to be rather insensitive to the harmonic structure and (site or bond) ordering. Using 139La NMR in La2NiO4.17, we show that in the 1/3 hole doped nickelate below the freezing temperature the stripes are strongly solitonic and site ordered with Ni3+ ions carrying S=1/2 in the domain walls and Ni2+ ions with S=1 in the domains.Comment: 4 pages including 4 figure

Nanoscale properties of superconducting cuprates probed by the electron paramagnetic resonance

The basic principles of EPR in the high-Tc materials are presented with the accent on the novel features of these compounds in comparison with the conventional metallic systems. An overview is given on the various results obtained in the past years with the emphasis on the analysis of the local properties. Among the issues discussed in the details are the unusual normal state properties, the magnetic fluctuations, the phonon effects, stripe phase and the nanoscale phase separation resulting from the interplay of the lattice distortions with the strong electron correlations. The special attention is focused on their relevance to the origin of the high-temperature superconductivity. The main conclusions followed from EPR experiments in the cuprates are discussed. Some recent developments are addressed and compared to theoretical models. © Springer-Verlag Berlin Heidelberg 2005

Nanoscale properties of superconducting cuprates probed by the electron paramagnetic resonance

The basic principles of EPR in the high-Tc materials are presented with the accent on the novel features of these compounds in comparison with the conventional metallic systems. An overview is given on the various results obtained in the past years with the emphasis on the analysis of the local properties. Among the issues discussed in the details are the unusual normal state properties, the magnetic fluctuations, the phonon effects, stripe phase and the nanoscale phase separation resulting from the interplay of the lattice distortions with the strong electron correlations. The special attention is focused on their relevance to the origin of the high-temperature superconductivity. The main conclusions followed from EPR experiments in the cuprates are discussed. Some recent developments are addressed and compared to theoretical models. © Springer-Verlag Berlin Heidelberg 2005

Nanoscale properties of superconducting cuprates probed by the electron paramagnetic resonance

The basic principles of EPR in the high-Tc materials are presented with the accent on the novel features of these compounds in comparison with the conventional metallic systems. An overview is given on the various results obtained in the past years with the emphasis on the analysis of the local properties. Among the issues discussed in the details are the unusual normal state properties, the magnetic fluctuations, the phonon effects, stripe phase and the nanoscale phase separation resulting from the interplay of the lattice distortions with the strong electron correlations. The special attention is focused on their relevance to the origin of the high-temperature superconductivity. The main conclusions followed from EPR experiments in the cuprates are discussed. Some recent developments are addressed and compared to theoretical models. © Springer-Verlag Berlin Heidelberg 2005