Field-dependent dielectric permittivity of paraelectric superlattice structures

SrTiO3/SrZrO3 and SrTiO3/BaTiO3 superlattice structures have been grown by pulsed laser deposition, and their dielectric properties have been measured at room temperature and at 77 K. The electric field-dependence of the permittivity of both types of structures exhibits a different behavior from that observed in the corresponding solid solutions Sr(TixZr1−x)O3 and (BaxSr1−x)TiO3, respectively. For the case of the SrTiO3/SrZrO3 superlattices, the data is compatible with the assumption that strain induces ferroelectricity in the SrTiO3 films at room temperature.