X‐ray diffraction and Raman study of nanogranular BaTiO 3 –CoFe 2 O 4 thin films deposited by laser ablation on Si/Pt substrates

Nanocomposite thin films composed by (BaTiO 3 ) 1– x –(CoFe 2 O 4 ) x with different cobalt ferrite concentrations ( x ) have been deposited by pulsed laser ablation on platinum covered Si(001) substrates. The films structure was studied by X‐ray diffraction and Raman spectroscopy. It was found that the CoFe 2 O 4 phase unit cell was compressed along the growth direction of the films, and it relaxed with increasing x . The opposite behavior was observed in the BaTiO 3 phase where the lattice parameters obtained from the X‐ray measurements presented a progressive distortion of its unit cell with increasing x . The presence of the strain in the films induced a blueshift of the Raman peaks of CoFe 2 O 4 that decreased with increasing CoFe 2 O 4 concentration. Cation disorder in the cobalt ferrite was observed for lower x , where the nanograins are more isolated and subjected to more strain, which was progressively decreased for higher CoFe 2 O 4 content in the films. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)