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We review the results of our recent studies of La2-xSrxCuO4 cuprate superconductor using electron paramagnetic resonance (EPR). It is shown that the EPR of Mn2+ doped into La2-xSrxCuO4 (LSCO) provides an unique microscopic information concerning the magnetic, electronic and lattice properties of cuprates. The main conclusions followed from these experiments are discussed. Most attention is given to important and highly debated questions, such as the role of the lattice, electron-phonon interaction, polaron formation and microscopic electronic phase separation in cuprates. [ABSTRACT FROM AUTHOR]

We study the stability of skyrmions in anisotropic layered magnets and consider a possible creation of the skyrmions in lightly doped layered cuprates. The picture of thermally excited and induced by the doped quasi-localized holes skyrmions is used to describe magnetic properties and spin kinetics of underdoped cuprates. A consistency of the skyrmion approach and the phase separation phenomenon is discussed. [ABSTRACT FROM AUTHOR]

In the low doping range of x from 0.01 to 0.06 in La2−xSrxCuO4, we observed two electron paramagnetic resonance (EPR) signals: a narrow and a broad one. The narrow line is ascribed to metallic regions in the material, and its intensity increases exponentially upon cooling below ∼ 150 K. The activation energy deduced Δ = 460(50) K is nearly the same as that found in the doped superconducting regime by Raman and neutron scattering. Obtained results provide evidence of the microscopic phase separation and two type of quasiparticles in lightly doped La2−xSrxCuO4 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]