The response function of domain growth processes, and in particular the violation of the fluctuation-dissipation theorem, are studied both analytically and numerically. In the asymptotic limit of large times, the fluctuation-dissipation ratio X, which quantifies this violation, tends to one if C...

The magnetic properties of (La<Subscript>1 − x </Subscript>Sr<Subscript> x </Subscript>)MnO<Subscript>3</Subscript> crystals have been studied. The ac susceptibility χ=χ′ + iχ″ has been measured at frequencies ranging from 10 Hz to 1 000 Hz. The x=0.25 crystal shows a typical ferromagnetic behaviour with a dimensionless SI susceptibility of 6 below T...</subscript></subscript></subscript></subscript>

We have performed an investigation of the nonlinear magnetic response in ruthenocuprates. A negative, diverging-like peak at the main magnetic transition T<Subscript>N</Subscript> in RuSr<Subscript>2</Subscript> RECu<Subscript>2</Subscript>O<Subscript>8</Subscript> (RE=Gd, Y) indicates a possible canted antiferromagnetic order. Another well defined feature above T<Subscript>N</Subscript> points to a blocking...</subscript></subscript></subscript></subscript></subscript>

We study the influence of interface effects on the magnetostatic modes propagating in a coupled ferromagnetic/antiferromagnetic bilayer. We assume that the magnetic layers are thick enough to be described by the bulk parameters and they are coupled through the interaction between the magnetic...

Employing the self-consistent Green's function approach, we studied the temperature dependence of the spin-wave stiffness in diluted magnetic semiconductors. Note that the Green's function approach includes the spatial and temperature fluctuations simultaneously which was not possible within...

We calculate the dynamical response of a group of non-interacting magnetic grains dispersed in a medium that imposes on them an uniaxial anisotropy. Numerical results are obtained for a collection of grains that has its volume distribution given by a Gaussian function centered in the average...