Magnetic Proximity Effect in YBa₂Cu₃O₇/La_2/3Ca_1/3MnO₃ and YBa₂Cu₃O₇/LaMnO₃₊ Superlattices

Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa₂Cu₃O₇ and ferromagnetic-metallic La0.67Ca0.33MnO₃ or ferromagnetic-insulating LaMnO₃₊. We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La0.67Ca0.33MnO₃ and almost absent for ferromagnetic-insulating LaMnO₃₊. We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature

Cluster-cluster aggregation for particles with different functionalities

An extended lattice model for reaction limited cluster-cluster aggregation is studied, where different kinds and states of bonds between monomers are considered. The decrease of the numbers of possible bonds per monomer yields decreasing fractal dimensions, which differ from the usual values obtained for diffusion limited and reaction limited cluster-cluster aggregation regimes, respectively