  Materials that crystalize in diamond-related lattices, with Si and GaAs as
their prime examples, are at the foundation of modern electronics.
Simultaneoulsy, the two atomic sites in the unit cell of these crystals form
inversion partners which gives rise to relativistic non-equilibrium spin
phenomena highly relevant for magnetic memories and other spintronic devices.
When the inversion-partner sites are occupied by the same atomic species,
electrical current can generate local spin polarization with the same magnitude
and opposite sign on the two inversion-partner sites. In CuMnAs, which shares
this specific crystal symmetry of the Si lattice, the effect led to the
demonstration of electrical switching in an antiferromagnetic memory at room
temperature. When the inversion-partner sites are occupied by different atoms,
a non-zero global spin-polarization is generated by the applied current which
can switch a ferromagnet, as reported at low temperatures in the diluted
magnetic semiconductor (Ga,Mn)As. Here we demonstrate the effect of the global
current-induced spin polarization in a counterpart crystal-symmetry material
NiMnSb which is a member of the broad family of magnetic Heusler compounds. It
is an ordered high-temperature ferromagnetic metal whose other favorable
characteristics include high spin-polarization and low damping of magnetization
dynamics. Our experiments are performed on strained single-crystal epilayers of
NiMnSb grown on InGaAs. By performing all-electrical ferromagnetic resonance
measurements in microbars patterned along different crystal axes we detect
room-temperature spin-orbit torques generated by effective fields of the
Dresselhaus symmetry. The measured magnitude and symmetry of the
current-induced torques are consistent with our relativistic density-functional
theory calculations.
