  Propulsion of the chiral magnetic nanomotors powered by a rotating magnetic
field is in the focus of the modern biomedical applications. This technology
relies on strong interaction of dynamic and magnetic degrees of freedom of the
system. Here we study in detail various experimentally observed regimes of the
helical nanomotor orientation and propulsion depending on the actuation
frequency, and establish the relation of these two properties with remanent
magnetization and geometry of the helical nanomotors. The theoretical
predictions for the transition between the regimes and nanomotor orientation
and propulsion speed are in excellent agreement with available experimental
data. The proposed theory offers a few simple guidelines towards the optimal
design of the magnetic nanomotors. In particular, efficient nanomotors should
be fabricated of hard magnetics, e.g., cobalt, magnetized transversally and
have the geometry of a normal helix with a helical angle of 35-45 degrees.
