  We predict that ferroelectric phase can be induced by the strong intrinsic
surface stress inevitably present under the curved surface in the high aspect
ratio cylindrical nanoparticles of nonferroelectric binary oxides (BaO, EuO,
MgO, etc). We calculated the sizes and temperature range of the ferroelectric
phase in BaO nanowires. The analytical calculations were performed within
Landau-Ginzburg-Devonshire theory with phenomenological parameters extracted
from the first principle calculations [E. Bousquet et al, Strain-induced
ferroelectricity in simple rocksalt binary oxides. arXiv:0906.4235v1] and
tabulated experimental data. In accordance with our calculations BaO nanowires
of radius ~(1-10) nm can be ferroelectric at room temperature (with spontaneous
polarization values up to 0.5 C/m2) for the typical surface stress coefficients
~ (10-50) N/m. We hope that our prediction can stimulate both experimental
studies of rocksalt binary oxides nanoparticles polar properties as well as the
first principle calculations of their spontaneous dipole moment induced by the
intrinsic stress under the curved surface.
