Static and Dynamic Charge Inhomogeneity and Crystal-Field Fluctuations for 4f Ions in High-Tc Cuprates.

The main mechanism in homogeneous broadening and relaxation of crystal-field excitations for R-ions in cuprates is believed to be provided by the fluctuations of crystalline electric field induced by a static and dynamic charge inhomogeneity generic to doped cuprates. Such an inhomogeneity is assumed to be the result of topological phase separation. We address the generalized granular model as one of the model scenarios for describing the static and dynamic charge inhomogeneity in cuprates. The charge subsystem is believed to be similar to that of a Wigner crystal with melting transition and phononlike positional excitation modes. We consider a simple model of charge inhomogeneity that allows us to elucidate the main universal features of the density of CF states and the respective inhomogeneous broadening. The formal description of R-ion relaxation mainly coincides with that of the recently suggested magnetoelastic mechanism by Lovesey and Staub. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]