The objective of this project is the theoretical investigation of magnetic properties and magnetization dynamics in simple and complex materials. Specifically, we aim to study the dynamics of magnetism (in the atomistic scale) in two different contexts: (i) magnetic materials of interest (from simple ferromagnets to composed alloys) that present an ultrafast demagnetization process when interacting with a light pulse; and (ii) topological spin textures, such as skyrmions, antiskyrmions, and other higher-order spin structures. Both contexts are currently attracting great attention from the condensed matter community, as they constitute viable alternatives to integrate new spintronic devices. The results obtained are intended to contribute to the understanding of the microscopic mechanisms that act in scenarios (i) and (ii). Depending on the material’s complexity (number of atoms in the unit cell, necessity to describe long-range interactions, low symmetry, etc), the simulations may require a high computational cost, from the Density Functional Theory calculation of properties and interaction parameters in the ground-state to parametrized coupled spin-lattice dynamics using phenomenological equations of motion.