One embodiment of a magnetic memory device comprises a substrate and a plurality of planar memory arrays stacked on the substrate, each memory array includes a plurality of parallel first conductive lines, each first conductive line includes a ferromagnetic cladding, a plurality of parallel second conductive lines overlapping the first conductive lines at a plurality of intersection regions, a plurality of magnetic tunnel junctions, each magnetic tunnel junction has a controllable electrical resistance, is disposed at an intersection region and electrically coupled to one of the first conductive lines at its first end and to one of the second conductive lines at its second end. The electrical resistance of the magnetic tunnel junction is controlled by a joint effect of a spin-polarized current running between the first and second ends and a bias magnetic field applied simultaneously to said each magnetic tunnel junction. Other embodiments are described and shown.