Diamond　NV center　Spin Probe

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.

(1) Nanoscale magnetic field sensing using nitrogen-vacancy center in diamond
Recently, nitrogen vacancy center (NV center) in diamond crystal is attracting much attention for utilizing it as a spin sensor (Fig. 2), since spin state existing in a combination of a carbon defect and nitrogen in diamond named as nitrogen-vacancy center (NV center) was 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 (Fig. 3). Especially, making a NV center as a scanning spin imaging probe (Fig. 4).

(2) Long-distance excitation of NV center via surface spin waves
We succeeded to excite NV center by spin waves; collective emotion of spins excited from 3.6 millimeter distance [1]. This will be new system to study interactions of spins.

(3) Development of scanning NV center spin sensing probe

Fig. 3, Scanning NV center diamond spin probe.
et al.: IEEE Magn. Lett. 1, 3500104 (2010)

(1) Nanoscale magnetic field sensing by using nitrogen-vacancy center in diamond

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 

Interaction of Spin and Heat

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)

(2) Interactions between spins and heat

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.

Scanning Microwave Microscopy

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)

(3) Spin wave imaging excited in a magnet by scanning microwave microscopy

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.