TY - JOUR
T1 - Anomalous spin Hall magnetoresistance in Pt/Co bilayers
AU - Kawaguchi, Masashi
AU - Towa, Daiki
AU - Lau, Yong Chang
AU - Takahashi, Saburo
AU - Hayashi, Masamitsu
N1 - Funding Information:
We thank S. Mitani for fruitful discussion. This work was partly supported by JSPS Grant-in-Aids for Specially Promoted Research (15H05702), Casio Foundation, and the Center of Spintronics Research Network of Japan. Y.-C.L. is a JSPS international research fellow.
Publisher Copyright:
© 2018 Author(s).
PY - 2018/5/14
Y1 - 2018/5/14
N2 - We have studied the spin Hall magnetoresistance (SMR), the magnetoresistance within the plane transverse to the current flow, of Pt/Co bilayers. We find that the SMR increases with increasing Co thickness: the effective spin Hall angle for bilayers with thick Co exceeds the reported values of Pt when a conventional drift-diffusion model is used. An extended model including spin transport within the Co layer cannot account for the large SMR. To identify its origin, contributions from other sources are studied. For most bilayers, the SMR increases with decreasing temperature and increasing magnetic field, indicating that magnon-related effects in the Co layer play little role. Without the Pt layer, we do not observe the large SMR found for the Pt/Co bilayers with thick Co. Implementing the effect of the so-called interface magnetoresistance and the textured induced anisotropic scattering cannot account for the Co thickness dependent SMR. Since the large SMR is present for W/Co but its magnitude reduces in W/CoFeB, we infer that its origin is associated with a particular property of Co.
AB - We have studied the spin Hall magnetoresistance (SMR), the magnetoresistance within the plane transverse to the current flow, of Pt/Co bilayers. We find that the SMR increases with increasing Co thickness: the effective spin Hall angle for bilayers with thick Co exceeds the reported values of Pt when a conventional drift-diffusion model is used. An extended model including spin transport within the Co layer cannot account for the large SMR. To identify its origin, contributions from other sources are studied. For most bilayers, the SMR increases with decreasing temperature and increasing magnetic field, indicating that magnon-related effects in the Co layer play little role. Without the Pt layer, we do not observe the large SMR found for the Pt/Co bilayers with thick Co. Implementing the effect of the so-called interface magnetoresistance and the textured induced anisotropic scattering cannot account for the Co thickness dependent SMR. Since the large SMR is present for W/Co but its magnitude reduces in W/CoFeB, we infer that its origin is associated with a particular property of Co.
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U2 - 10.1063/1.5021510
DO - 10.1063/1.5021510
M3 - Article
AN - SCOPUS:85047253193
VL - 112
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 20
M1 - 202405
ER -