Fieldlike spin-orbit torque in ultrathin polycrystalline FeMn films
Open Access
- 3 March 2016
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 93 (9), 094402
- https://doi.org/10.1103/physrevb.93.094402
Abstract
Fieldlike spin-orbit torque in FeMn/Pt bilayers with ultrathin polycrystalline FeMn has been characterized through planar Hall effect measurements. A large effective field of to is obtained for FeMn in the thickness range of 2–5 nm. The experimental observations can be reasonably accounted for by using a macrospin model under the assumption that the FeMn layer is composed of two spin sublattices with unequal magnetizations. The large effective field corroborates the spin Hall origin of the effective field, considering the much smaller uncompensated net moments in FeMn as compared to NiFe. The effective absorption of spin current by FeMn is further confirmed by the fact that spin current generated by Pt in NiFe/FeMn/Pt trilayers can only travel through the FeMn layer with a thickness of 1–4 nm. By quantifying the fieldlike effective field induced in NiFe, a spin diffusion length of 2 nm is estimated in FeMn, consistent with values reported in the literature by ferromagnetic resonance and spin-pumping experiments.
Keywords
Funding Information
- National Research Foundation-Prime Minister's office, Republic of Singapore (NRF-CRP10-2012-03)
- Ministry of Education - Singapore (MOE2013-T2-2-096)
- Agency for Science, Technology and Research (IMRE/10-1C0107)
- National Natural Science Foundation of China (11274321, 51525103)
- National Science Foundation (ECCS-1404542)
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