Field-temperature evolution of the magnetic state of [Fe(1.2Â Ã )/Cr(10.5Â Ã )]30 structure by Mössbauer reflectometry with synchrotron radiation

Nanostructured epitaxial [57Fe(1.2 Å)/Cr(10.5 Å)]30 multilayer with ultrathin Fe layers, demonstrated Kondo-like behavior, has been investigated by means of the nuclear resonance reflectivity at low temperatures (down to 4 K) in magnetic fields up to 4 T. We detected the beginning of the magnetic phase transition at 150 K which correlates with the minimum on the electrical resistivity curve. The determined magnetic hyperfine field distribution P(Bhf) indicates an inhomogeneity of the iron environments. When we apply the very high external magnetic field up to 4 T, it aligns Bhf(i) along the direction of the external field only partially. Also it has been noticed that Bhf(i) orientations depend on the magnetic pre-history.