Nosaki Laboratory - Elucidating the Microscopic Theory of Spin Dynamics Using Resonance Phenomena

At the Nosaki Laboratory at Keio University, we study the dynamics of electron spins, which are responsible for the magnetism of ferromagnetic materials.

Electron spin, one of the angular momenta of an electron, undergoes a precessional motion called precession when placed in a magnetic field, much like a spinning top in a gravitational field. However, because a state where the magnetization is not aligned with the magnetic field has high magnetic energy, this energy dissipates over time, and the precessional motion eventually damps. The relaxation time of the magnetization precession is about one nanosecond (one-billionth of a second), but in next-generation magnetic devices with operating speeds faster than this relaxation speed, this precessional motion has a significant impact.

Therefore, to reverse magnetization both energy-efficiently and at high speed, the Nosaki Laboratory is focusing on the resonance phenomena of magnetization and is advancing research on new methods of magnetization reversal using microwaves.