Josephson Diode Effect in Helimagnetic CrNb₃S₆

Cr_1/3NbS₂ is a helimagnetic transition metal dichalcogenide, meaning it has broken inversion symmetry and time reversal symmetry. We explore the magnetic diffraction patterns of Josehpson junctions fabricated from Cr_1/3NbS₂, and find that there is a zero-field Josehpson diode effect, as well as highly asymmetric responses to field in the patterns. We also propose two explanations for these observations, one based on the emergence of vortices from stray magnetic fields, and one based on non-zero spin chirality from stray magnetic fields.