Hayashi Group | Quantum Spintronics/Photonics

　The quantum physics of electron spins and photons

News

Studies on the DMI and spin orbit torque at the Ir/Co interface published.

The DMI of the Ir and Co interface is found to be similar in magnitude with that of the Pt and Co interface.
The sign of the Ir/Co DMI is the same with that of the Pt/Co interface.
Ir has small a spin Hall angle of 0.01 but acts as a good spin sink, which can be exploited for engineering spin orbit torque in spin orbit heterostructures.

Dzyaloshinskii-Moriya interaction and spin-orbit torque at the Ir/Co interface
Y. Ishikuro, M. Kawaguchi, N. Kato, Y.-C. Lau and M. Hayashi
Phys. Rev. B 99, 134421 (2019).

Our paper on the spin Hall effect in Co-Ga alloy is published.

Spin Hall angle of ~0.05 is found in an alloy formed from elements with relatively small spin spin orbit coupling.
First principle calculations show that hybridization of the Co 3d and Ga 4p orbitals contribute to the large spin Hall effect in this alloy.

Spin Hall effect from 3d-4p hybridized orbitals
Y.-C. Lau, H. Lee, G. Qu, K. Nakamura, and M. Hayashi
Phys. Rev. B 99, 064410 (2019).

Hana Hirose won the JSAP young scientist presentation award!

Hana Hirose won the 45th young scientist presentation award for her presentation at the 79th Japan Applied Physics Society (JSAP) autumn meeting.
Presentation title: "Material dependence of interfacial spin-momentum locked bands in metallic heterostructures."
Congratulations!

Our paper was selected as a featured article!

Circular photogalvanic effect in Cu/Bi bilayers
H. Hirose, N. Ito, M. Kawaguchi, Y. C. Lau, M. Hayashi
Appl. Phys. Lett. 113, 222404 (2018).

See also Scilight for more information.

Spin orbit induced photocurrent found in Bi/Cu bilayer.

Irradiation of circularly polarized light in the visible range generates a helicity dependent photocurrent in Cu/Bi bilayers.
The effect can arise from a spin momentum locked band at the Cu/Bi interface.

Circular photogalvanic effect in Cu/Bi bilayers
H. Hirose, N. Ito, M. Kawaguchi, Y. C. Lau, M. Hayashi
Appl. Phys. Lett. 113, 222404 (2018).

Spin orbit torque detected optically!

The spin orbit torque of W/CoFeB/MgO and Pt/CoFeB/MgO heterostructures are studied using magneto-optical Kerr effect. Signals from the current induced torque and current induced heating are separated using a double modulation scheme.

Optical Detection of Spin-Orbit Torque and Current-Induced Heating
Y. Marui, M. Kawaguchi, M. Hayashi
Appl. Phys. Express 11, 5 093001 (2018).

Hana Hirose won the Best presentation award!

Hana Hirose won the Best presentation award at the Condensed Matter Physics Summer School.
Congratulations!

Our paper on the resistance of chiral domain walls is published.

Resistance associated with chiral domain walls is studied. Contributon form the anomalous Hall effect dominates the domain wall resistance, but we also find effects that can be attributed to the chiral magnetoresistance.

Domain-Wall Resistance in Cofeb-Based Heterostructures with Interface Dzyaloshinskii-Moriya Interaction
Y. Ishikuro, M. Kawaguchi, Y. C. Lau, Y. Nakatani, and M. Hayashi
Appl. Phys. Express 11, 5 073001 (2018).

Our paper on the spin Hall magnetoresistance in Pt/Co bilayers is published.

An anomalously large spin Hall magnetoresistance (SMR) is found in Co/Pt bilayers. The effective spin Hall angle derived from the SMR approaches 0.4, indicating that the measured SMR includes contribution from other spin dependent effect.

Anomalous Spin Hall Magnetoresistance in Pt/Co Bilayers
M. Kawaguchi, D. Towa, Y. C. Lau, S. Takahashi, and M. Hayashi
Appl. Phys. Lett. 112, 5 202405 (2018).

Our paper on the observation of spin Nernst effect is published.

The spin Nernst effect in Tungsten
P. Sheng, Y. Sakuraba, Y.-C. Lau, S. Takahashi, S. Mitani, M. Hayashi
Science Advances 3, e1701503 (2017). [OPEN ACCESS]

Densly packed chiral domain walls can be moved in sync!

Current induced generation and synchronous motion of highly packed coupled chiral domain walls
R. P. del Real, V. Raposo, E. Martinez, M. Hayashi
Nano Lett. 17, 1814 (2017).

Our paper on electric field modulation of PMA is published.

Electric field modulation of the non-linear areal magnetic anisotropy energy
Y.-C. Lau, P. Sheng, S. Mitani, D. Chiba, M. Hayashi
Appl. Phys. Lett. 110, 022405 (2017).

Our paper on the mass of chiral domain walls is published.

Tunable inertia of chiral magnetic domain walls
J. Torrejon, E. Martinez, M. Hayashi
Nature Comm. 7, 13533 (2016. [OPEN ACCESS]

Review paper on spin orbit effects published.

Spin–Orbit Effects in CoFeB/MgO Heterostructures with Heavy Metal Underlayers
J. Torrejon, J. Kim, J. Sinha, M. Hayashi
SPIN 6, 1640002 (2016). [OPEN ACCESS]

Our paper on spin Hall magnetoresistance in metallic bilayers is published.

Spin Hall magnetoresistance in metallic bilayers
J. Kim, P. Sheng, S. Takahashi, S. Mitani, M. Hayashi
Phys. Rev. Lett. 116, 097201 (2016).