A ferromagnetic tunnel junction is disclosed. The ferromagnetic tunnel
junction includes a pinned magnetic layer, a tunnel insulating film
formed on the pinned magnetic layer, and a free magnetic multilayer body
formed on the tunnel insulating film. The free magnetic multilayer body
includes a first free magnetic layer, a diffusion barrier layer, and a
second free magnetic layer stacked in this order on the tunnel insulating
film. The first free magnetic layer and the second free magnetic layer
are ferromagnetically coupled with each other. The diffusion barrier
layer inhibits the additive element contained in the first free magnetic
layer from diffusing into the second free magnetic layer.