Crystal structure and magnetoresistance of vacancy-ordered perovskite SrV₀.₃Fe₀.₇O₂.₈ at low temperature

Vacancy-ordering in perovskite oxides brings a rich variety of structures and accompanying physical properties. Previously, we reported room-temperature magnetoresistance in SrV₀.₃Fe₀.₇O₂.₈ with ordered oxygen vacancies in the primitive perovskite (111)ₚ plane. In this report, we characterize the structure and physical properties of SrV₀.₃Fe₀.₇O₂.₈ at low temperatures. This compound undergoes a structural phase transition from the rhombohedral phase to the monoclinic phase by cooling down to 𝘛ₛ = 200 K. The transition induces octahedral tilting, affecting its magnetization behaviour: The compound shows weak ferromagnetism with almost zero coercivity above 𝘛ₛ, while the coercivity prominently increases below 𝘛ₛ, keeping its weak ferromagnetism. We also observed an enhancement of magnetoresistance by decreasing temperature, reaching -18% at 130 K and 9 T.