The focus of our research is the physics of small scale ferromagnetic
structures, typically with nanometer sizes or artificial structure on the nanometer scale. We approach physics at this scale using both "top-down" and "bottom-up" methods.
In the top-down approach we use nanofabrication techniques combined with thin film deposition. The former enables the realization of materials and electronic devices with sub-100 nm lateral sizes (i.e., in a plane or cross-section), while the latter permits atomic scale control in the growth direction (i.e., the perpendicular direction). We are investigating magnetic nanopillars and the nature of interaction between an electrical current and the magnetization. For example, an electric current can excite dynamical states of the magnetization and even change the direction of the magnetization of a nanomagnet, in phenomena known as spin-transfer. We have recently shown how such currents can be used to coherently control magnetization dynamics in nanomagnets.
In the bottom-up approach 3-dimensional molecular structures are synthesized chemically. Here we study materials known as single molecule magnets.
Single molecule magnets consist of a core of strongly exchange-coupled transition metal ions with a large collective magnetic moment per molecule, thus far up to about 30 Bohr magnetons, or 30 times the magnetic moment of an electron. They also have a uniaxial magnetic anisotropy, that forces the magnetic moment to point either up or down along an axis. These materials enable study of strong collective quantum effects, such as magnetic quantum tunneling and coherence, as well as the ultimate limit to magnetic miniaturization