Structure induced quasi-diamagnetism, spin-glass behaviors and exchange bias in crystalline Mn3.5Au0.5N films

Abstract

Homogeneous Au doped crystalline Mn4N films are grown on MgO (100) substrates by plasma assisted molecular beam epitaxy. Au0 and Mn0 occupy the corner sites in the Mn4N crystal lattice, while Mn1+ atoms are located at face-centered sites, respectively. Mn2p peaks with a shift to the low binding energy side and pronounced spin-glass behaviors as well as exchange bias effects (EB) are presented after the introduction of Au atoms. Mn3.5Au0.5N films exhibit spin-glass behaviors in the temperature range of 15 K to 266 K. Giant exchange bias effects with a 2.16 KOe of positive shift are observed at 100 K in 30 KOe of magnetic field. Spin-glass behaviors disappear at about 266 K and exchange bias effects decrease almost simultaneously to zero at this temperature. We propose that the giant EB in Mn3.5Au0.5N originates from the global interaction between two magnetic sublattices.