Ferromagnetic resonance and magnetization switching characteristics of perpendicular magnetic tunnel junctions with synthetic antiferromagnetic free layers
deyuan lyu, Delin Zhang, Daniel Gopman, Yang Lv, Onri Benally, Jian-Ping Wang
Perpendicular magnetic tunnel junctions (pMTJs) with synthetic antiferromagnetic (SAF) free layers were predicted and recently demonstrated to possess ultrahigh switching speed and ultralow switching current density. However, ferromagnetic resonance (FMR) characterization and systemic investigations of their magnetization switching behavior remains limited. Here, we prepare SAF free layer-based pMTJs (SAF-pMTJs) with a Ru/Ta bilayer coupling spacer. The composite SAF free layer shows a Gilbert damping constant of 0.019 in the FMR measurements. In device level studies that span from 900 nm down to 200 nm lateral size,, we observe a transition of the SAF from a preferred antiparallel to parallel magnetization configuration at small device sizes, which can be explained by the increased dipole interaction. The impact of operating current is also investigated. We report an extraordinarily strong dependence, up to 144.1 kOe per A/μm2, of the offset field on the applied current, indicating the electric-field modulation on the interlayer exchange coupling. These results will be instructive to the designincrease understanding of the material properties and device performance of SAF-pMTJs for ultrafast, ultralow-power consumption spintronics devices.
, Zhang, D.
, Gopman, D.
, Lv, Y.
, Benally, O.
and Wang, J.
Ferromagnetic resonance and magnetization switching characteristics of perpendicular magnetic tunnel junctions with synthetic antiferromagnetic free layers, Applied Physics Letters, [online], https://doi.org/10.1063/5.0075043, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933345
(Accessed November 29, 2023)