In-plane anisotropic magnetoresistance and planar Hall effect in off-stoichiometric single crystal Mn3Ga

We report the observation of in-plane anisotropic magnetoresistance (AMR) and planar Hall effect in our recently discovered kagome antiferromagnetic off-stoichiometric single crystal of Mn3Ga. We found that the in-plane AMR is dominated by a sixfold symmetry at low temperature due to the kagome lattice magnetocrystalline anisotropy. However, an unusual fourfold symmetry is also revealed by the angular-dependent AMR measurements, which originates from the little distortion of the crystal accompanying the slight ferromagnetic transition. Moreover, we also found a clear planar Hall effect signal in off-stoichiometric single crystal of Mn3Ga, which may be related to the chiral anomaly, one of the signatures of the magnetic Weyl fermions.