Magnetic properties of mechanically milled nanosized Mn

Nanosized Mn powders were fabricated by milling Mn flakes in pure ethyl alcohol followed by homogenization. XRD analysis confirms single-phase characterization of the product and shows it has a grain size of 40 nm. The ZFC and FC magnetizations exhibit a large irreversibility with onset of about 60 K. The fit of the Curie-Weiss relation indicates strong AFM interaction in the considered system. A large coercive field and shifted hysteresis loops, i.e. He = 83.6 kA/m, are observed at 5 K in the 2 T field cooling case. The analysis indicates that surface anisotropy can lead to the occurrence of large exchange bias.