Structural comparative study by RBS and XPD of stoichiometric and Bi-deficient SrBi2Nb2O9 thin films epitaxially grown on (1 0 0)SrTiO3

The influence of the Bi content on the structural characteristics of SrBi2Nb2O9 (m = 2 phase) thin films was studied. Epitaxial growth of c-axis oriented m = 2 films and the epitaxial intergrowth of m = 2 and a m = 3 type phases was achieved on (1 0 0)SrTiO3 single crystals in stoichiometric or Bi-deficient films, respectively. These two types of samples were analyzed both by X-ray photoelectron diffraction and Rutherford backscattering spectroscopy in channeling mode. High crystalline quality of the films was confirmed by χmin values down to 6%. Some local structural modifications between the m = 2 and 3 phases were deduced from the collected XPD data using a simple approach, based on forward scattering effects. XPD modulations and RBS channeling directions were proved to be in good agreement, evidencing a structural coherence all over the thickness of the films and corroborating the assumption of an intergrowth mechanism for Bi-deficient films firstly suggested by X-ray diffraction patterns.