Stabilization of antiferromagnetic order in FeO nanolayers.

We have studied the evolution of the magnetic state of a nanometer thick antiferromagnetic (AFM) FeO layer during its formation using nuclear resonant scattering of synchrotron radiation. In contact to ferromagnetic Fe, the FeO layer does not show magnetic order at room temperature (RT). Once embedded between two Fe layers, magnetic coupling to the adjacent ferromagnets leads to a drastic increase of the Néel temperature far above RT, while the blocking temperature remains below 30 K. The presented results evidence the role that the ferromagnetic surrounding plays in modifying the magnetic state of ultrathin AFM layers.