Mössbauer spectra and electric properties of 57Fe-enriched BiFeO3 thin films

• Published in: Japanese Journal of Applied Physics Vol. 53; no. 9S
• Main Authors: Tanaka, Kiyotaka, Fujita, Yuya, Okamura, Soichiro, Yoshida, Yutaka
• Format: Journal Article
• Language: English
• Published: The Japan Society of Applied Physics 03.09.2014
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.53.09PA15

57Fe-enriched BiFeO3 (BFO) thin films are fabricated on Pt/Ti/SiO2/Si substrates from a stoichiometric precursor solution by chemical solution deposition process. The microstructure of the thin films is controlled by a changing the sintering time at 550 °C. The polycrystalline thin film fabricated at 550 °C for 5 min shows well-saturated polarization-electric field (P-E) hysteresis loops and the remnant polarization Pr and coercive field Ec at room temperature are 52 µC/cm2 and 365 kV/cm, respectively, at an applied electric field of 1200 kV/cm. The Mössbauer spectra show that the BFO thin film has the valence state of Fe3+ only, consisting of antiferromagnetic and paramagnetic components. The paramagnetic component with an area fraction from 11 to 18%, which is not amorphous or Bi2Fe4O9, seems to distribute in the surface shell of the grains and the grain boundaries. This component must strongly influence the ferroelectric properties at room temperature.