  Deterministic control of domain walls orthogonal to the direction of current
flow is demonstrated by exploiting spin orbit torque in a perpendicularly
polarized Ta/CoFeB/MgO multilayer in presence of an in-plane magnetic field.
Notably, such orthogonal motion with respect to current flow is not possible
from traditional spin transfer torque driven domain wall propagation even in
presence of an external magnetic field. Reversing the polarity of either the
current flow or the in-plane field is found to reverse the direction of the
domain wall motion. From these measurements, which are unaffected by any
conventional spin transfer torque by symmetry, we estimate the spin orbit
torque efficiency of Ta to be 0.08.
