Example embodiments relate to magnetic memory devices and methods for manufacturing the same. The magnetic memory device includes a magnetic tunnel junction layer including a first magnetic layer, a second magnetic layer, and a first tunnel barrier layer between the first and second magnetic layers. The second magnetic layer is disposed on the first tunnel barrier layer and is in direct contact with the first tunnel barrier layer. The second magnetic layer includes cobalt-iron-beryllium (CoFeBe). A beryllium content of CoFeBe in the second magnetic layer ranges from about 2 at % to about 15 at %.