Lanthanum distribution in SrBi4−xLaxTi4O15

The Raman spectra for SrBi4−xLaxTi4O15 (x=0.00-1.00) ceramic samples are investigated to explore the influence of doping on the structure of SrBi4Ti4O15. Lanthanum-doping results in the shifts of the Raman modes involved in the vibration of the cations at A site of the pseudo-pervoskite slabs, Bi3+ ions in the Bi2O2 layers, and the stretching mode of TiO6 octahedra. The shifts of these modes indicate that La3+ ions prefer the A site of SrBi4Ti4O15 as x≤0.10, and as x>0.10, they are incorporated into Bi2O2 layers.