  We show that the type-II multiferroic properties of bulk MnWO4 are kept in
nanostructured ceramics of 50 nm grain size prepared via spark plasma sintering
(SPS). This means that ferroelectric polarization is robust against downsizing,
which is at variance with standard ferroelectrics like BaTiO3. We ascribe this
stability to the spin-driven nature of the ferroe-lectric correlations in
type-II multiferroics while it is resulting from lattice distortion in other
cases. This may open the way for persistent type-II multiferroicity with no
need for external stabilization like substrate-generated strain.
