A magnetic memory device is provided including a magnetic tunnel junction pattern having a free pattern, a reference pattern, and a tunnel barrier pattern between the free pattern and the reference pattern. The free pattern includes a first sub-free pattern, a second sub-free pattern, and a third sub-free pattern. The first sub-free pattern is between the tunnel barrier pattern and the third sub-free pattern, and the second sub-free pattern is between the first sub-free pattern and the third sub-free pattern. The second sub-free pattern includes nickel-cobalt-iron-boron (NiCoFeB), and the third sub-free pattern includes nickel-iron-boron (NiFeB). Related methods of fabrication are also provided.