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- Growth temperature dependence of crystal symmetry in Nb doped BaTiO3 thin films
Growth temperature dependence of crystal symmetry in Nb doped BaTiO3 thin films
in: Journal of Advanced Dielectrics (2013)
Growth temperature effects on the microstructure of 2 at.-% Nb-doped BaTiO3 thin films are studied using x-ray diffraction and transmission electron microscopy (TEM). Reciprocal space maps and electron diffraction patterns show that the a-axis lattice parameter increases and the c-axis parameter decreases with increasing growth temperature, indicating a decrease of tetragonality. Films grown at 800 °C are cubic at room temperature. Bright-field TEM images show low and high densities of threading defects in films grown at low and high temperatures, respectively. The observations are
discussed in terms of a hindering of the cubic-to-tetragonal phase transition by a high defect density and a high unit cell volume.