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Oxygen vacancies are not merely defects in materials but play a crucial role in determining their mechanical, optical, electrical, and catalytic properties.[1] Understanding and controlling these vacancies is essential for the development of advanced energy conversion and storage technologies.[2] SrCoO₂.₅ exhibits a brownmillerite structure with alternating layers of metal–oxygen octahedra and tetrahedra. When grown on SrTiO₃ (STO) substrates, the oxygen vacancy channels (OVCs) are typically aligned horizontally.[2] Tuning these OVCs strongly influences magnetic anisotropy and resistive switching behavior, which is important for memristor applications. In this work, BM-SCO thin films were deposited on Pb(Mg₁/₃Nb₂/₃)O₃–PbTiO₃ (PMN-PT) and BaTiO₃ (BTO) substrates using pulsed laser deposition. The lattice parameters of PMN-PT (4.0 Å) and BTO (3.994 Å) induce sufficient strain to transform horizontal OVCs into vertical ones without ionic liquid gating. The structural and magnetic properties of films grown on STO, PMN-PT, and BTO were systematically compared. Additionally in SRO/SCO/Nb-STO heterostructures, XRD measurements reveal a bias-induced topotactic phase transition from brownmillerite SrCoO₂.₅ to perovskite SrCoO₃ (Figure 2), driven by electric-field-controlled oxygen migration. XRD and magnetization (M–T and M–H) measurements confirm the orientation and evolution of OVCs. These tunable vacancy channels enable fast ionic transport, offering promising opportunities for energy storage, neuromorphic devices, and oxide electronics.[3]
| Scientific Topics | Solid State Physics |
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