Ferroelectricity in SrTiO3 nanocrystalline disks

SrTiO3 and CaTiO3 conventional bulk materials are incipient ferroelectrics. In this note, we report for the first time that ferroelectricity could occur in SrTiO3 nanocrystalline disks even at room temperature. The peak in the temperature dependence of permittivity for a CaTiO3 nanocrystalline disk at a low temperature is also observed. The observed ferroelectricity (or permittivity peak) in SrTiO3 (or CaTiO3) nanocrystalline disks could be attributed to the strain effect.