Strong damping-like spin-orbit torque and tunable Dzyaloshinskii-Moriya interaction generated by low-resistivity Pd${}_{1-x}$Pt${}_x$ alloys

Abstract

Despite their great promise for providing a pathway for very efficient and fast manipulation of magnetization at the nanoscale, spin-orbit torque (SOT) operations are currently energy inefficient due to a low damping-like SOT efficiency per unit current bias, and/or the very high resistivity of the spin Hall materials. Here, we report an advantageous spin Hall material, Pd1-xPtx, which combines a low resistivity with a giant spin Hall effect as evidenced through the use of three independent SOT ferromagnetic detectors. The optimal Pd0.25Pt0.75 alloy has a giant internal spin Hall ratio of >0.47 (damping-like SOT efficiency of ~ 0.26 for all three ferromagnets) and a low resistivity of ~57.5 μΩ cm at 4 nm thickness. Moreover, we find the Dzyaloshinskii-Moriya interaction (DMI), the key ingredient for the manipulation of chiral spin arrangements (e.g. magnetic skyrmions and chiral domain walls), is considerably strong at the Pd1-xPtx/Fe0.6Co0.2B0.2 interface when compared to that at Ta/Fe0.6Co0.2B0.2 or W/Fe0.6Co0.2B0.2 interfaces and can be tuned by a factor of 5 through control of the interfacial spin-orbital coupling via the heavy metal composition. This work establishes a very effective spin current generator that combines a notably high energy efficiency with a very strong and tunable DMI for advanced chiral spintronics and spin torque applications.

Submitted to Advanced Functional Materials on Augest 21, 2018

References in corpus (4)

• Study of Intrinsic Spin Hall Effect and Orbital Hall Effect in 4d- and 5d- Transition Metals
• Spin-orbit torques in heavy metal/ferromagnet bilayers with varying strength of interfacial spin-orbit coupling
• Interface enhanced spin-orbit torques and current-induced magnetization switching of Pd/Co/AlO${}_x$ layers
• Suppression of the fieldlike spin-orbit torque efficiency due to the magnetic proximity effect in ferromagnet/platinum bilayers

Cited by in corpus (7)

• Enhancing spin-orbit torque by strong interfacial scattering from ultra-thin insertion layers
• Benchmarking of spin-orbit torque switching efficiency in Pt alloys
• Transverse and Longitudinal Spin-Torque Ferromagnetic Resonance for Improved Measurements of Spin-Orbit Torques
• Enhancement of spin transparency by interfacial alloying
• Energy-efficient ultrafast SOT-MRAMs based on low-resistivity spin Hall metal Au0.25Pt0.75
• Materials Requirements of High-Speed and Low-Power Spin-Orbit-Torque Magnetic Random-Access Memory
• Intrinsic nature of the giant spin Hall conductivity of Pt