  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 {\mu}{\Omega} 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.
