Symmetry-engineered and electrically tunable in-plane anomalous Hall effect in oxide heterostructures

The anomalous Hall effect has long served as a cornerstone for uncovering low-dissipation quantum phenomena and powering Hall-based functionalities, yet its tunability and device application are constrained by the orthogonal relationship among electric field, Hall current, and out-of-plane magnetization in thin-film geometry. The recently emerged in-plane anomalous Hall effect, a transverse Hall response driven by in-plane magnetization, promises to unlock Hall readout of planar magnetic orders and spin textures. However, in sharp contrast to the conventional anomalous Hall effect, experimentally accessible and effective control strategies for the in-plane anomalous Hall effect remain largely undeveloped, impeding its transition from phenomenological observation to device implementation. Here we establish a symmetry-engineered, electrically tunable in-plane anomalous Hall effect in epitaxial CaRuO3/La2/3Ca1/3MnO3/CaRuO3 heterostructures grown on NdGaO3(110). By exploiting CaRuO3-buffer-controlled mirror-symmetry breaking in the ferromagnetic La2/3Ca1/3MnO3 layer, we achieve a robust in-plane anomalous Hall effect that faithfully mirrors square-shaped ferromagnetic hysteresis, providing a direct Hall readout of in-plane magnetization reversal. Ionic liquid gating further enables dynamic reconfiguration of the symmetry breaking, achieving wide-range electrical modulation and fully reversible ON/OFF switching of the in-plane anomalous Hall effect. This highly tunable platform offers a symmetry-based probe of emergent low-dimensional magnetism and facilitates the development of programmable Hall functionalities in planar device geometries. The authors demonstrate that engineering crystal symmetry in oxide heterostructures creates a robust in-plane anomalous Hall effect, enabling direct readout of in-plane magnetization and a wide range of fully reversible electrical ON/OFF switching.