  Current-induced electron spin polarization is shown to produce nuclear
hyperpolarization through dynamic nuclear polarization. Saturated fields of
several millitesla are generated upon the application of electric field over a
timescale of a hundred seconds in InGaAs epilayers and measured using optical
Larmor magnetometry. The dependence on temperature, external magnetic field,
and applied voltage is investigated. We find an asymmetry in which the
saturation nuclear field depends on the relative alignment of the electrically
generated spin polarization and the external magnetic field, which we attribute
to an interplay between various electron spin dynamical processes.
