The various implementations described herein include methods, devices, and systems for fabricating magnetic memory devices. In one aspect, a method of fabricating a magnetic memory device includes: (1) providing a dielectric substrate with a metallic core protruding from the dielectric substrate, where: (a) a first portion of the metallic core is surrounded by the dielectric substrate and a second portion of the metallic core protrudes away from a surface of the dielectric substrate; and (b) the second portion includes: (i) a surface offset from the surface of the dielectric substrate and (ii) sidewalls extending away from the surface of the dielectric substrate to the offset surface; (2) depositing a first ferromagnetic layer on exposed surfaces of the metallic core and the dielectric substrate; (3) depositing a spacer layer on exposed surfaces of the first ferromagnetic layer; and (4) depositing a second ferromagnetic layer on exposed surfaces of the spacer layer.