Spin-orbit-torque- (SOT) induced magnetization switching in a $\mathrm{Co}$/$\mathrm{Pt}$/$\mathrm{Co}$ trilayer, with two $\mathrm{Co}$ layers exhibiting magnetization easy axes orthogonal to each other is investigated. A $\mathrm{Pt}$ layer is used as a source of spin-polarized current as it is characterized by relatively high spin-orbit coupling. The spin Hall angle of $\mathrm{Pt}$, $\theta =0.08$, is quantitatively determined using the spin-orbit-torque ferromagnetic resonance technique. In addition, $\mathrm{Pt}$ serves as a spacer between two $\mathrm{Co}$ layers and depending on its thickness, different interlayer-exchange-coupling (IEC) energy between ferromagnets is induced. Intermediate IEC energies, resulting in a top $\mathrm{Co}$ magnetization tilted from the perpendicular direction, allows for SOT-induced field-free switching of the top $\mathrm{Co}$ layer. The switching process is discussed in more detail, showing the potential of the system for neuromorphic applications.

• Received 13 March 2019
• Revised 9 May 2019

DOI:https://doi.org/10.1103/PhysRevApplied.12.014006