Fast polarization switching capability mediated by oxygen deficiency in Co-substituted SrFeO3-δ perovskites

Abstract

In this study, a series of eco-friendly, oxygen-deficient SrFe1-xCoxO3-δ (x = 0.00, 0.33, 0.66, and 1.00) perovskite samples was prepared via a sol–gel-based auto-combustion route. Analysis of X-ray diffraction data confirmed the synthesis of the single-phase cubic perovskite structure for x = 0.00 to x = 0.66, whereas SrCoO3-δ had a single-phase tetragonal structure. The lattice constants decreased as the Co contents increased due to the smaller ionic radii of Co4+ ions. Field emission scanning electron microscopy images showed that the grain size decreased initially, but the size increased with the increase in Co substitution above x = 0.33. Ferroelectric behavior was analyzed under an electric field of 50 V/cm with a frequency of 50 Hz. The unsaturated polarization–electric field loops for SrFeO3-δ indicated relaxor-type ferroelectric behavior. The maximum polarization (Pmax) and remanent polarization (Pr) both decreased as the Co contents increased. The maximum recoverable energy density was recorded for SrFeO3-δ. However, the maximum energy storage efficiency of 66% was obtained for the SrFe0.67Co0.33O3 sample. These findings demonstrate that members of the SrFe1-xCoxO3-δ series, particularly with x = 0.33, could be potential candidates for use in energy and data storage devices, mainly due to the high value of Pmax − Pr, superior storage efficiency, and rapid polarization switching ability.