  We have performed a principle-proof-experiment of a magneto-optical
diffraction (MOD) technique that requires no energy level splitting by
homogeneous magnetic field and a circularly polarized optical lattice, avoiding
system errors in an interferometer based on the MOD. The principle for this new
MOD is that asynchronized switching of quadrupole trap and Ioffe trap in a
quadrupole-Ioffe-configuration trap can generate a residual magnetic force to
drive a Bose-Einstein condensate (BEC) to move. We have observed asymmetric
atomic diffraction resulting from the asymmetric distribution of the Bloch
eigenstates involved in the diffraction process when the condensate is driven
by such a force, and matter-wave self-imaging due to coherent population
oscillation of the dominantly occupied Bloch eigenstates. We have classified
the mechanisms that lead to symmetric or asymmetric diffraction, and found that
our experiment presents a magnetic alternative to a moving optical lattice,
with a great potential to achieve a very large momentum transfer ($>110 \hbar
k$) to a BEC using well-developed magnetic trapping techniques.
