A magnetic memory device including a magnetic tunnel junction is provided. The magnetic tunnel junction includes a fixed layer, a polarization enhancement structure on the fixed layer, a tunnel barrier layer on the polarization enhancement structure, and a free layer on the tunnel barrier layer, wherein the polarization enhancement structure includes a plurality of polarization enhancement layers and at least one spacer layer which separates the plurality of polarization enhancement layers from each other. A thickness of each of the plurality of polarization enhancement layers is from 5 Å to about 20 Å, and a thickness of the at least one spacer layer is from about 2 Å to about 15 Å.