Phase-sensitive ferromagnetic resonance detections using stroboscopic magneto-optical Kerr effect
Seungha Yoon (Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD, USA)

Spin currents can be used to change the magnetization direction via spin-transfer torque effects. These spin-transfer torque effects are more efficient that magnetic fields in small devices, and therefore, spin-transfer torque has been widely investigated for future spintronic devices such as magnetic random access memory and oscillators. Ferromagnetic resonance is very useful for measuring dynamic magnetic torques, and the phase of magnetic precession provides information about the direction of these torques. Therefore, phase-sensitive ferromagnetic resonance detection has been received attention interest for characterizing spin-transfer torque efficiency.
In this talk, I will introduce two phase-sensitive ferromagnetic resonance detection methods that use the magneto-optical Kerr effect. Phase-sensitive detection is made possible using laser amplitude-modulation with the same (homodyne method) or slightly shifted frequency (heterodyne method) relative to the spin precession frequency. I will compare these detection methods, and discuss the details of experimental setup and the advantages for future applications.