Spintronics has been a highly fertile research area especially over the last two decades, giving rise to practical developments such as read heads of hard drives, nonvolatile magnetic memory, and other types of magnetic sensors.
The key ingredient in this field is to utilize the spin degree of freedom in currents and materials to achieve the desired functionality, in particular with an eye to providing a feasible alternative to semiconductor technology. One of the main obstacles to overcome in this regard is the high energy cost associated with, e.g., Joule heating when passing a spin-polarized current consisting of electrons through a device. Presently, very high current densities are needed to perform magnetization switching via current-induced spin-transfer torque. As an alternative mechanism to spin-transfer torque which could circumvent the Joule heating from electrons, magnon-induced magnetization dynamics has been investigated more recently.
The topic of controllable domain wall motion is receiving much attention due to its potential with regard to the storage and transfer of information. A domain wall is a topological defect in a magnetic system where the local magnetic order parameter typically rotates spatially in a fashion that reduces the net magnetic moment of the domain wall area. Owing to their small size (order 10 nm) and large velocities (order 100 m/s), controllable domain wall motion holds real potential for tailoring functional devices with fast writing speeds. In addition, there have been several proposals related to magnetic memory functionality due to the nonvolatile nature of magnetic domains. Walker breakdown is nevertheless a limiting factor in this regard.
In our research, we are investigating various phenomena related to magnetization dynamics such as domain wall motion, ferromagnetic resonance, and spin pumping.