The Heusler ferromagnetic (FM) compound $\mathrm{C}{\mathrm{o}}_2\mathrm{FeAl}$ interfaced with a high spin-orbit coupling nonmagnetic (NM) layer is a promising candidate for energy-efficient spin-logic circuits. The circuit potential depends on the strength of angular momentum transfer across the FM/NM interface, hence requiring low spin-memory loss and high spin-mixing conductance. To highlight this issue, spin pumping and spin torque ferromagnetic resonance measurements have been performed on $\mathrm{C}{\mathrm{o}}_2\mathrm{FeAl}/\beta$-Ta heterostructures tailored with Cu interfacial layers. The interface tailored structure yields an enhancement of the effective spin-mixing conductance. The interface transparency and spin-memory loss corrected values of the spin-mixing conductance, spin Hall angle, and spin-diffusion length are found to be $3.40\pm 0.01\times {10}^{19}{\mathrm{m}}^{-2}$, $0.029\pm 0.003$, and $2.3\pm 0.5\mathrm{nm}$, respectively. Furthermore, a high current modulation of the effective damping of around $2.1\%$ has been achieved at an applied current density of $1\times {10}^9\mathrm{A}/{\mathrm{m}}^2$, which clearly indicates the potential of using this heterostructure for energy-efficient control in spin devices.

• Received 2 April 2019
• Revised 14 November 2019

DOI:https://doi.org/10.1103/PhysRevB.100.214433