Suppression of standing spin waves in low-dimensional ferromagnets.

We examine the experimental absence of standing spin wave modes in thin magnetic films, by means of atomistic spin dynamics simulations. Using Co on Cu(001) as a model system, we demonstrate that by increasing the number of layers, the optical branches predicted from adiabatic first-principles calculations are strongly suppressed, in agreement with spin-polarized electron energy loss spectroscopy measurements reported in the literature. Our results suggest that a dynamical analysis of the Heisenberg model is sufficient in order to capture the strong damping of the standing modes.

Ising-like behaviour of mesoscopic magnetic chains.

We demonstrate an experimental realization of the short range magnetic order in a one-dimensional Ising chain using fabricated mesospins. We confirm an excellent agreement between the experimental findings and simulations obtained using the original Ising model. In particular, we are able to show that the thermal behaviour of the mesoscopic Ising chain dominates over the thermal behaviour of the individual mesospins themselves, confirming that fabricated mesospins can be viewed as artificial magnetic atoms.

Atomistic spin dynamics and surface magnons.

Atomistic spin dynamics simulations have evolved to become a powerful and versatile tool for simulating dynamic properties of magnetic materials. It has a wide range of applications, for instance switching of magnetic states in bulk and nano-magnets, dynamics of topological magnets, such as skyrmions and vortices and domain wall motion. In this review, after a brief summary of the existing investigation tools for the study of magnons, we focus on calculations of spin-wave excitations in low-dimensional magnets and the effect of relativistic and temperature effects in such structures. In general, we find a good agreement between our results and the experimental values. For material specific studies, the atomistic spin dynamics is combined with electronic structure calculations within the density functional theory from which the required parameters are calculated, such as magnetic exchange interactions, magnetocrystalline anisotropy, and Dzyaloshinskii-Moriya vectors.

Dimensionality and confinement effects in δ-doped Pd(Fe) layers.

We address the dimensionality aspects of the magnetic ordering in δ-doped Pd(Fe) structures. The key property we investigate, via magneto-optic Kerr measurements, is the magnetization induced by iron in palladium, over a wide temperature range 5 K < T < 300 K. The dimensional crossover we observe cannot be rationalized on the basis of structural considerations alone, since we find the dimensionality of the low temperature and of the critical region can differ. We discuss the crossover in terms of the temperature dependence of the magnon modes, giving rise to lower dimensionality at low temperatures.