Published online by Cambridge University Press: 01 July 2005
Perovskite-based SrNb0.2Ti0.8O3/La0.7Sr0.3MnO3 bilayer films were grown on (001) SrTiO3 substrate. By means of in situ transmission electron microscopy, lattice expansion and double periodicity were identified in both plan-view and cross-section La0.7Sr0.3MnO3 films under electron irradiation for 25 s. After the electron beam was removed from specimens, the original perovskite structure recovered within 10 min. However, when irradiation time was more than 1 min, the original perovskite structure could not recover and became an amorphous phase or a cavity created by irradiation. According to first-principle calculation and electron diffraction pattern simulation, formation mechanism of the lattice expansion and double periodicity is proposed based on oxygen deficiency during electron irradiation.