Influence of substrate temperature in BiFeO3-CoFe2O4 nanocomposites deposited on SrTiO3 (0 0 1)

BiFeO3-CoFe2O4 epitaxial nanocomposites have been deposited on SrTiO3 (0 0 1) substrates by pulsed laser deposition. We present here a study of the influence of the deposition temperature (TS), in the 550-800 oC range, on the film composition, morphology and microstructure. Electron-probe microanalysis shows strong reduction of the Bi content in the films when increasing TS. Films prepared at TS=750 oC and above are virtually Bi-free. X-ray diffraction (XRD) data show that, due to the volatility of Bi, there is a progressive reduction in the amount of BiFeO3. The deposition temperature and the concomitant presence of FexOy spurious phases in the nanocomposites grown at high temperature promote radical changes in film morphology and magnetization. It thus follows that a temperature range suitable for controlled modification of nanocomposites morphology would be extremely narrow.