Formation of magnetite in bismuth ferrrite under voltage stressing

Abstract

Micro-Raman studies show that under $\sim 700\mathrm{kV}∕\mathrm{cm}$ of dc voltage stressing for a few seconds, magnetite ${\mathrm{Fe}}_3{\mathrm{O}}_4$ forms in thin-film bismuth ferrite $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ , probably due to phase separation. No evidence is found spectroscopically of hemite $\alpha \text{-}{\mathrm{Fe}}_2{\mathrm{O}}_3$ , maghemite $\gamma \text{-}{\mathrm{Fe}}_2{\mathrm{O}}_3$ , or ${\mathrm{Bi}}_2{\mathrm{O}}_3$ . This may relate to the controversy regarding the magnitude of magnetization in $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ .