Manipulation and Electrical Detection of the Néel vector in Cr₂O₃ Thin Films

The ability to electrically detect and manipulate the Néel vector in antiferromagnetic (AFM) materials opens new possibilities for AFM spintronic applications. In this work, we systematically investigate Cr₂O₃ (0001) thin films grown on platinum using pulsed laser deposition (PLD). PLD grown films are shown to be of exceptional quality based on high resolution x-ray diffraction. Electrical transport measurements on Pt/Cr₂O₃/Pt heterostructure devices reveal a magnetic field driven reorientation of the Néel vector. Top and bottom anomalous Hall effect (AHE) devices show opposite signed jumps in the signals showing a sharp reorientation of the order parameter and then a broad spin-flop transition in films as thin as 14 nm. Our results highlight two key differences between films and bulk. Firstly, the ordering parameter in films exhibits magnetic control. Secondly, the top and bottom AHE devices show distinct additional AFM domains features. In the films and a clear trend that is revealed as the films get thicker the 180° flip of the Néel vector reorientation happens at larger magnetic fields, eventually merging with that of the spin-flop field. Additionally, we observe temperature dependence in the Néel vector reorientation: as the temperature decreases, the reorientation field required becomes larger. These insights highlight critical factors involved in film growth and domains and offer guidance for the future of spintronic applications.