Materials Property Division

Surface and Interface Research

Eiji  SAITOH PHOTO
Prof. Eiji SAITOH(WPI)
Assoc.Prof. Saburo TAKAHASHI
Assist. Prof. Yuki SHIOMI
Assist. Prof. Ryo IGUCHI

Harvesting energy by micro angular momentum: spin, photon, and MEMS

We are exploring novel physical phenomenon regarding electron spin. Spin is a quantum mechanical rotation of electrons inherent to the theory of relativity. Using this quantum mechanical rotation with nanotechnologies, we are challenging to establish physical principles of spintronics.

Spin current, a fl ow of spin angular momentum, is a critical component of spintronics. We are one of the global pioneers in the research of spin current and have succeeded in experimentally proving signal transmission and energy harvesting by the spin current. One of the highlights is the fi nding of spin Seebeck effect, where the electron spin works like a turbine and converts thermal heat into workable electricity. Another challenge is driving a mechanics using the quantum angular momentum of electron. Recently, we proved the spin can couple with the motion of liquid fl ow. It opened the new horizon of spin based mechanics and further development with MEMS is a promising adventure.

We are the leading team in such new area of spin based science focusing on the use of microscopic rotations.

spin, spintronics, spin current, spin seebeck effet, spinmechanics
Observation of spin hydrodynamic generation. The voltage originated from spin current was observed when the liquid metal fl ows in the capillary. The spatial gradient of the vortices in the liquid fl ow works as an effective magnetic fi eld on spins and drives the spin current.s

Observation of spin hydrodynamic generation. The voltage originated from spin current was observed when the liquid metal fl ows in the capillary.
The spatial gradient of the vortices in the liquid fl ow works as an effective magnetic fi eld on spins and drives the spin current.s

Observation of an unidirectional heat fl ow by a spin current excited by a microwave. The disk was heated at the direction of the spin current rather than at the radiation point of the microwave. ©Nature Publishing Group

Observation of an unidirectional heat fl ow by a spin current excited by a microwave. The disk was heated at the direction of the spin current rather than at the radiation point of the microwave. ©Nature Publishing Group

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