Spin Hall Effect in Ru_xPt_1-x Alloy Over the Entire Composition Range

We have studied the spin Hall effect in Ru_xPt_1-x alloys over the entire composition range from x = 0 to 1. Pt is characterized by a large spin Hall effect and strong spin-orbit coupling while Ru is a common metal widely used in spintronic devices for interlayer exchange coupling. Both metals are highly stable and electronically rich in properties. We anticipate that the Ru_xPt_1-x system exhibits an enhanced spin Hall effect yet has relatively low resistivities which reduce electrical power consumption in potential spintronic devices. This alloy system has also been proposed as a promising candidate for studying three-dimensional magnetic spin textures due to the interlayer Dzyaloshinskii-Moriya interaction that is notably enhanced by the composition variation. We report high-quality samples verified by low resistivities and large spin Hall angles through various measurement techniques including magnetometry, electron- and magneto-transport. Our results promote the Ru_xPt_1-x system as a strong contender for the development of low-current-density applications with large charge-to-spin conversion ratios and, alternatively, a metallic solid with smoothly varying properties for spintronic devices.