Anelastic measurements of the dynamics of lattice, charge and magnetic inhomogeneities in cuprates and manganites

An overview is presented of the information obtained by anelastic spectroscopy on the low frequency dynamics of various types of intrinsic lattice and electronic inhomogeneities in some cuprate superconductors and manganites. Results are presented on the collective and local pseudodiffusive tilt modes of the o octahedra in multiwell potentials in La2-xSrxCuO4; the fast dynamics of the local motion is determined by atomic tunneling and direct coupling with the hole excitations. Two anelastic relaxation processes are identified as due to the motion of the hole stripes. One occurring in the cluster spin glass phase is attributed to the motion between the dopant atoms acting as pinning points, and is completely blocked within the LTT structure. Another process around 80 K is attributed to the depinning of the stripes in a disordered state. In La1-xCaxMnO3 a glassy dynamic response below the ferromagnetic transition is attributed to the charge-ordered nanodomains.