Steplike anomalous Hall behaviors in mixed-phase BiFeO₃-based heterostructure

The heterostructures based on multiferroic BiFeO3 (BFO) have received much attention for the great potential in magnetoelectric coupling and spintronic applications. Therefore, the BFO films combined with rhombohedral (R) phase and tetragonal (T) phase can bring in various functionalities. Here, we demonstrate that the Ta/Pt/Co/Pt multilayers grown on R-, T-, and mixed-phase BFO exhibit perpendicular magnetic anisotropy. We find that the magnetic switching behavior of the multilayer is sensitive to the phase of the BFO layer. The Ta/Pt/Co/Pt layers grown on top of the pure R- or T-phase BFO show one-step anomalous Hall effect (AHE) switching. However, the layers grown on the mixed-phase BFO show steplike AHE switching. We attribute that the steplike switching behavior originates from the two different interfacial situations between mixed-phase BFO and above layers. Our results bring a potential avenue for realizing spintronic devices based on mixed-phased BFO.