- Hysteresis properties of thin films and multilayers
- Magnetization states of bulk nanocomposites
- High frequency properties of patterned magnetic structures
We perform numerical simulations of quasistatic hysteresis processes of thin polycrystalline magnetic films (with the thicknesses up to ~ 100 nm) and multilayers composed of such films, which may be also separated by non-magnetic spacers. Such studies reveal an intrinsic relation between the shape and basic characteristics of hysteresis loops (remanence and coercivity) on one side, and magnetic and geometric parameters of these films and multilayers on the other side.
Using the recently developed polyhedron meshing algorithm and our new micromagnetic software basing on this paradigm, we are able to simulate magnetization state and hysteresis loops of bulk magnetic nanocomposite, i.e. magnetic materials made of several magnetic and non-magnetic phases where each phase may consist of nanosized crystal grains or be amorphous. Comparison of our simulation results with the small-angle magnetic neutron scattering (SANS) data obtained on such materials enables to gain unique information about the internal magnetic configuration of nanocomposites and the influence of various magnetic and structural parameters of these materials on their magnetic properties.
Our group investigates the magnetization behavior of artificially patterned thin film nanoelements (nanoarrays) in oscillating magnetic fields with microwave frequencies. Numerical analysis of this behavior allows to study the dependence of, e.g., ac-susceptibilty of nanoarrays on the size, shape and magnetic parameters of constituent nanoelements.
In addition to studies outlined in the previous paragraph, we are also simulating the propagation of spin waves (magnons) in arrays of magnetic nanostripes and nanoelements. Together with simulations of magnon eigenmodes in such systems our modeling fully covers the rapidly developing field of magnonics – area of the solid state magnetism investigating the behavior of spin wave excitations in patterned magnetic arrays. One of the results of our simulations is the possibility to optimize in advance properties of various magnonic devices, like spin wave refractors, filters, mirrors etc.
In this area we have a long track of research highlights on simulations of magnetization dynamics induced by a spin-polarized current (SPC), including both the steady-state magnetization precession caused by such a current and the fast SPC-induced magnetization switching. Among the systems studied by our group are magnetic nanopillars, extended multilayers where the current is injected via point contacts and arrays of magnetic nanoelements where we have studied synchronization processes of corresponding spin-torque driven nanooscillators (STNOs).