MOCVD of BiFeO3 thin films on SrTiO3
Résumé
Abstract Bi‐Fe‐O thin films are grown by liquid‐injection metal‐organic (MO)CVD on (001) SrTiO3 substrates using two different bismuth precursors, Bi(tmhd)3 and Bi(mmp)3. The precursor Bi(mmp)3 is found to be more effective for Bi incorporation in the films. Epitaxial BiFeO3 films are obtained and no evidence for secondary phases such as Fe2O3 or Bi2O3 is found by X‐ray diffraction (XRD) or transmission electron microscopy (TEM) studies. However, the presence of a multiple binding environment for Fe3+ is shown from the X‐ray photoelectron spectroscopy (XPS) analyses. Moreover, XPS shows evidence of a Fe2+/Fe3+ valence mixed state. A saturation magnetization of 70 emu cm–3 is measured. This value is much higher than that reported for the bulk BiFeO3 material. Both the double valence for Fe ions and the enhanced magnetization may originate in the presence of non‐fully‐oxidized γ‐Fe2O3.
Domaines
Chimie
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