Domain Wall-Dependent Electrical Transport in a Magnetic Weyl Semimetal

Magnetic force microscopy reveals that microscale lamellae fabricated by focused ion beam microscopy of Co₂MnGa—a ferromagnetic Weyl semimetal—contain just a few magnetic domains which form a pattern that is different on the top surface than on the bottom. Transport measurements of electrical devices made from these lamellae with contacts on both faces show large resistance anisotropies that depend on in-plane and out-of-plane magnetic fields in different ways. These data taken together describe a very non-homogeneous current distribution which may result from the interaction of the Weyl fermions in this material with the magnetic domain walls.