We focus on study of sensing "spin dynamics"in magnet and its control. We explore novel phenomena related to spin dynamics and extract the fundamental physics behind for the application to the spin device and the magnetic sensor device. For this purpose, highly sensitive and high-resolution spatial imaging methods are developed.
Fig. 3, Scanning NV center diamond spin probe.
et al.: IEEE Magn. Lett. 1, 3500104 (2010)
Recently, nitrogen vacancy center (NV center) in diamond crystal is attracting much attention for utilizing it as a spin sensor, since single spin state existing in a combination of a carbon defect and nitrogen in diamond named as nitrogen-acancy center (NV center) vwas demonstrated to be detected through fluorescence measurement (Gruber and Wrachtup, et al., Science, 276, 2012 (1997)). Interestingly, this optically detected magnetic resonance (ODMR) can be used for sensing spins existing around. Especially, making a NV center as a scanning probe, imaging of the spin
Fig.1 Spin wave heat conveyer effect, Using spin wave, collective motion of spins, energy conveyed is converted into heat.
T. An, et al.: Nature Materials, 12, 549-553 (2013)
Recently, magnetization dynamics such as magnetic domain-wall motion and 'spin waves' is drawing attention as a suitable system to study new field of 'spin caloritronics' ; focusing on the interaction of spins with heat current in materials. We study this interplay of spin wave and heat, and control spins by heats and vice versa.
Fig. 2, Spin-wave imaging by using scanning microwave microscopy. Spin-wave modes excited on a YIG magnetic film by using microwave probe.
T. An, et al.: IEEE Magn. Lett. 1, 3500104 (2010)
A local excitation of ferromagnetic resonance (FMR) and spin waves; collective motions of spins in magnets, are detected by using a scanning radio-frequency (RF) probe. Spatial distribution of spin dynamics having different precession amplitude is imaged that is useful for studying quantized or localized spin-wave modes.