  We report the first observation of superconductivity in heterostructure
consisting of an insulating ferroelectric film (Ba$_{0.8}$Sr$_{0.2}$TiO$_3$)
grown on an insulating parent compound of La$_2$CuO$_4$ with [001] orientation.
The heterostructure was prepared by magnetron sputtering on a
non-atomically-flat surface with inhomogeneities of the order of 1-2 nm. The
measured superconducting transition temperature T$_c$ is about 30K. We have
shown that superconductivity is confined near the interface region. Application
of a weak magnetic field perpendicular to the interface leads to the appearance
of the finite resistance. That confirms the quasi-two-dimensional nature of the
superconductive state. The proposed concept promises ferroelectrically
controlled interface superconductivity which offers the possibility of novel
design of electronic devices.
