Structural, dielectric, and magnetic properties of epitaxially grown BaFeO3 thin films on (100) SrTiO3 single-crystal substrates

We have prepared single-crystalline films of ${\mathrm{BaFeO}}_3,$ which may contain high valent ${\mathrm{Fe}}^{\text{4+}}$ ions, on (100) ${\mathrm{SrTiO}}_3$ substrates by pulsed laser-beam deposition. The reflection high-energy electron diffraction patterns for the films apparently show a $C_{\mathit{4}}$ symmetry operation, suggesting that the sample had a pseudocubic perovskite structure rather than hexagonal unit cell. The films were found to be highly insulating, and showed a high value of dielectric constant of $\text{ε=59.}$ At 300 K, the magnetization loop of the film apparently shows hysteresis, as well as small remanent magnetization. These characteristics are totally different from those of bulk ${\mathrm{BaFeO}}_3.$