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Freestanding perovskite thin films display many unprecedented properties and exhibit the potential to be easily integrated on other non-oxide substrates or layers. In this work, we demonstrated a pathway to synthesis freestanding perovskite oxide thin films by using brownmillerite SrCoO2.5 as a sacrificial layer. Four representative freestanding perovskite oxide films, e.g., ferromagnetic SrRuO3, La0.7Sr0.3MnO3, dielectric SrTiO3, and ferroelectric Pb(Zr0.2Ti0.8)O3, were produced by etching SrCoO2.5 in Fe(NO3)3 weak acidic solution at room temperature. A 80 nm SrRuO3, which served as an H+ conduction channel, was deposited as a bottom layer of SrCoO2.5 to trigger a quick dissolution for the exfoliation of SrTiO3 and Pb(Zr0.2Ti0.8)O3 poor H+ conductor. Their crystal structure and physical properties were well retained in transferred films. Our work demonstrated the wide applicability of SrCoO2.5 as a sacrificial layer on the synthesis of freestanding perovskite oxide thin films. [ABSTRACT FROM AUTHOR]

Large data storage at reduced dimension is of a great deal of interest in spintronic devices in which magnetic oxide films lead for realizing the modulation of perpendicular magnetic anisotropy (PMA). Herein, we report the modulation of PMA in oxide heterostructures composed of one manganite layer sandwiched between two cobaltite layers, i.e., LaCoO3−δ/La0.7Sr0.3MnO3/LaCoO3−δ via oxygen vacancies. The PMA is originated by the orbital reconstruction and ferromagnetic exchange interaction at the interface between the CoO6 and MnO6 octahedra layers. The modulation ratio up to a significant value ∼200% of PMA can be realized through the phase transition of LaCoO3−δ layers between perovskite and brownmillerite via deprivation or replenishment of oxygen sites. The antiferromagnetic superexchange interaction at the interface between the oxygen-deficient CoO4 tetrahedra layer and the adjacent MnO6 octahedral layer with lattice distortion may suppress the magnetization and PMA. This work ensures promising outcomes in situ modulation of PMA in oxide films such as ferroelectric polarization or ionic liquid gating via the transport of oxygen vacancies. [ABSTRACT FROM AUTHOR]