  Charge dipole moment and spin moment rarely coexist in single-phase bulk
materials except in some multiferroics. Despite the progress in the past
decade, for most multiferroics their magnetoelectric performance remains poor
due to the intrinsic exclusion between charge dipole and spin moment. As an
alternative approach, the oxide heterostructures may evade the intrinsic limits
in bulk materials and provide more attractive potential to realize the
magnetoelectric functions. Here we perform a first-principles study on
LaAlO$_3$/PbTiO$_3$ superlattices. Although neither of the components is
magnetic, magnetic moments emerge at the ferroelectric domain walls of
PbTiO$_3$ in these superlattices. Such a twist between ferroelectric domain and
local magnetic moment, not only manifests an interesting type of
multiferroicity, but also is possible useful to pursuit the electrical-control
of magnetism in nanoscale heterostructures.
