Electrically Detecting Néel Vector Switching in Cr₂O₃ via Spin Hall and Magnetic Proximity Effects

Antiferromagnetic (AFM) materials offer significant advantages over ferromagnets for spintronic applications, particularly in terms of compact integration and ultrafast operations. However, reliable electrical detection of Néel vector states remains a major challenge. In this work, we demonstrate an unambiguous electrical detection of the Néel vector in a Cr₂O₃(0001)/Pt heterostructure via a combination of the spin Hall planar Hall effect (PHE) and magnetic-proximity-induced anomalous Hall effect (AHE).

Both the PHE and AHE signals, associated with the in-plane Néel vector above the spin-flop field and the net induced out-of-plane magnetic moment in Pt, respectively, were extracted using the spinning current method. A series of Pt Hall cross patterns with different widths ranging from 50 um to 0.1 um were fabricated by photolithography and electron beam lithography. We observed that the AHE signal consists of a field-symmetric AHE component and a field-antisymmetric component. Under different field cooling conditions, the AHE signals could be toggled between two distinct states, while zero-field cooling selects one of two states, indicating the existence of bistable single-domain states. Additionally, we found that AHE signal magnitudes were independent of the device size in devices below 10 um, further confirming the single domain states. These results demonstrate magnetic field manipulation and sensitive electrical detection of the 90° and 180° Néel vector switching in Cr₂O₃ nanodevices.