TY - JOUR
T1 - Spin-Pumping-Free Determination of Spin-Orbit Torque Efficiency from Spin-Torque Ferromagnetic Resonance
AU - Okada, Atsushi
AU - Takeuchi, Yutaro
AU - Furuya, Kaito
AU - Zhang, Chaoliang
AU - Sato, Hideo
AU - Fukami, Shunsuke
AU - Ohno, Hideo
N1 - Funding Information:
The authors thank J. Llandro, T. Hirata, H. Iwanuma, and K. Goto for their technical support and discussion. A portion of this work was supported by the ImPACT Program of CSTI, JST-OPERA, JSPS KAKENHI Grants No. 17H06093, No. 16J05455, and No. 18KK0143, and RIEC Cooperative Research Projects. Y.T. acknowledges the Graduate Program in Spintronics, Tohoku University.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/7/23
Y1 - 2019/7/23
N2 - Spin-torque ferromagnetic resonance (ST-FMR) provides a useful tool to investigate various magnetic properties in spintronic systems, where one excites FMR by applying a rf current and detects the dc voltage generated through rectification effects. While this scheme has been used to characterize spin-orbit torques (SOTs) that have attracted much attention recently, it is known that dc voltages can also be generated by spin pumping that overlaps with the signal from the rectification effects. Here, we show a method to determine the SOT generation efficiency by ST-FMR free from spin pumping using two representative material systems, W/Co-Fe-B/MgO and Pt/Co/MgO. In addition, using the values determined by the method, which are confirmed to agree well with the results of a separately performed extended harmonic Hall measurement, we also quantify the amount of overestimation if the results obtained by a conventional ST-FMR setup are analyzed without considering the spin pumping. The present finding offers a useful insight to obtain a reliable value of SOT efficiency using ST-FMR, in particular for systems that exhibit large SOT, which accompanies large spin pumping.
AB - Spin-torque ferromagnetic resonance (ST-FMR) provides a useful tool to investigate various magnetic properties in spintronic systems, where one excites FMR by applying a rf current and detects the dc voltage generated through rectification effects. While this scheme has been used to characterize spin-orbit torques (SOTs) that have attracted much attention recently, it is known that dc voltages can also be generated by spin pumping that overlaps with the signal from the rectification effects. Here, we show a method to determine the SOT generation efficiency by ST-FMR free from spin pumping using two representative material systems, W/Co-Fe-B/MgO and Pt/Co/MgO. In addition, using the values determined by the method, which are confirmed to agree well with the results of a separately performed extended harmonic Hall measurement, we also quantify the amount of overestimation if the results obtained by a conventional ST-FMR setup are analyzed without considering the spin pumping. The present finding offers a useful insight to obtain a reliable value of SOT efficiency using ST-FMR, in particular for systems that exhibit large SOT, which accompanies large spin pumping.
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U2 - 10.1103/PhysRevApplied.12.014040
DO - 10.1103/PhysRevApplied.12.014040
M3 - Article
AN - SCOPUS:85073643781
SN - 2331-7019
VL - 12
JO - Physical Review Applied
JF - Physical Review Applied
IS - 1
M1 - 014040
ER -