MOCVD of BiFeO₃ Thin Films on SrTiO₃

Abstract

Abstract Bi‐Fe‐O thin films are grown by liquid‐injection metal‐organic (MO)CVD on (001) SrTiO 3 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 BiFeO 3 films are obtained and no evidence for secondary phases such as Fe 2 O 3 or Bi 2 O 3 is found by X‐ray diffraction (XRD) or transmission electron microscopy (TEM) studies. However, the presence of a multiple binding environment for Fe 3+ is shown from the X‐ray photoelectron spectroscopy (XPS) analyses. Moreover, XPS shows evidence of a Fe 2+ /Fe 3+ valence mixed state. A saturation magnetization of 70 emu cm –3 is measured. This value is much higher than that reported for the bulk BiFeO 3 material. Both the double valence for Fe ions and the enhanced magnetization may originate in the presence of non‐fully‐oxidized γ‐Fe 2 O 3 .