TY - JOUR
T1 - Enhancement of room-temperature unidirectional spin Hall magnetoresistance by using a ferromagnetic metal with a low Curie temperature
AU - Yamanoi, Kazuto
AU - Semizu, Hikari
AU - Nozaki, Yukio
N1 - Funding Information:
This work was partially supported by JSPS KAKENHI Grant No. JP18H03867, JST CREST Grant No. JPMJCR19J4, Grant-in-Aid for Research Activity start-up No. 19K23588, and The Murata Science Foundation, Japan.
Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/10/1
Y1 - 2022/10/1
N2 - The unidirectional spin Hall magnetoresistance (USMR) effect is useful to detect the direction of magnetization in a ferromagnetic metal/nonmagnetic metal bilayer, which is the typical geometry used in a spin-orbit torque switching device. In this Letter, we demonstrate the enhancement of the USMR effect by reducing the Curie temperature TC of the ferromagnetic (FM) layer in a FM/platinum bilayer. The USMR ratio was maximized when the thickness of each FM layer was consistent with the spin diffusion length. We found that the maximum USMR ratio can be doubled by replacing Ni81Fe19 (TC=854 K) with Ni85Cu15 (TC=527 K) as the FM. This enhancement of the USMR effect is attributed to an increase of electron-magnon scattering in accordance with Bloch law. We also found that the use of ferromagnets with face-centered-cubic structures, such as Ni, Ni81Fe19, and Ni85Cu15, increased the USMR effect relative to that of body-centered-cubic Fe.
AB - The unidirectional spin Hall magnetoresistance (USMR) effect is useful to detect the direction of magnetization in a ferromagnetic metal/nonmagnetic metal bilayer, which is the typical geometry used in a spin-orbit torque switching device. In this Letter, we demonstrate the enhancement of the USMR effect by reducing the Curie temperature TC of the ferromagnetic (FM) layer in a FM/platinum bilayer. The USMR ratio was maximized when the thickness of each FM layer was consistent with the spin diffusion length. We found that the maximum USMR ratio can be doubled by replacing Ni81Fe19 (TC=854 K) with Ni85Cu15 (TC=527 K) as the FM. This enhancement of the USMR effect is attributed to an increase of electron-magnon scattering in accordance with Bloch law. We also found that the use of ferromagnets with face-centered-cubic structures, such as Ni, Ni81Fe19, and Ni85Cu15, increased the USMR effect relative to that of body-centered-cubic Fe.
UR - http://www.scopus.com/inward/record.url?scp=85141032531&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85141032531&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.106.L140401
DO - 10.1103/PhysRevB.106.L140401
M3 - Article
AN - SCOPUS:85141032531
SN - 2469-9950
VL - 106
JO - Physical Review B
JF - Physical Review B
IS - 14
M1 - L140401
ER -