Spintronics exploits the spin of electrons to control an electric current flow in nanoscale ferromagnetic/nonmagnetic/ ferromagnetic (FM/NM/FM) heterostructures. This has led to the discovery of a large variety of new physical effects such as the Spin Momentum Transfer, which provides a completely new method for controlling the magnetization state in nanoscale heterostructures. Here spin momentum is transferred from the conduction electrons to the local magnetization. Large angle steady state (i.e. non-damped) magnetization oscillations are an important result of this effect. Here the spin momentum transfer acts as an energy feedback to counteract natural damping. It provides a unique opportunity to study non-linear magnetization dynamics effects in confined magnetic nanostructures, not accessible in other ways. The conversion of such magnetization oscillations into a large output voltage makes such nanoscale devices also of interest for microwave applications such as for wide band frequency generation, frequency detection or dynamic field sensing. Development of such applications is done in collaboration with LETI and requires improving the general microwave performances, such as the phase noise characteristics via tuning of the non-linear properties. In this thesis project a new magnetic structure will be explored consisting of a magnetic multilayer structure. This leads to collective excitations due to the mutual coupling of the different layers via exchange, dipolar fields and spin transfer torque. Such coupling is expected to reduce the linewidth characteristics.

The student will contribute to the realization of the devices, realize the microwave measurements aand analyse the results in the frame of theoretical models using also numerical modeling.