A magnetic memory device includes a free layer and a guide layer on a substrate. An insulating layer is interposed between the free layer and the guide layer. At least one conductive bridge passes through the insulating layer and electrically connects the free layer and the guide layer. A diffusion barrier may be interposed between the guide layer and the insulating layer. The device may further include a reference layer having a fixed magnetization direction on a side of the free layer opposite the insulating layer and a tunnel barrier between the reference layer and the free layer. Related fabrication methods are also described.