Network patterns and strength of orbital currents in layered cuprates

In a frame of the $t-J-G$ model we derive the microscopical expression for the circulating orbital currents in layered cuprates using the anomalous correlation functions. In agreement with $\mu$-on spin relaxation ($\mu$SR), nuclear quadrupolar resonance (NQR) and inelastic neutron scattering(INS) experiments in YBa$_2$Cu$_3$O$_{6+x}$ we successfully explain the order of magnitude and the monotonous increase of the {\it internal} magnetic fields resulting from these currents upon cooling. However, the jump in the intensity of the magnetic fields at T$_c$ reported recently seems to indicate a non-mean-field feature in the coexistence of current and superconducting states and the deviation of the extended charge density wave vector instability from its commensurate value {\bf Q}$\approx(\pi,\pi$) in accordance with the reported topology of the Fermi surface

89Y nuclear spin-lattice relaxation in SrY2O4:Ho3+ single crystals

Measurements of 89Y nuclear spin-lattice relaxation in SrY2O4:Ho3+ crystals for the magnetic field B parallel to the crystal c axis show that 89Y at T < 20 K relaxes due to fluctuating magnetic field created only by Ho13+ transitions between the ground and the first excited Zeeman sublevels of the 5I8 multiplet