Magnetic aftereffect and magnetization processes of nanocrystalline /spl alpha/-Fe/Nd/sub 2/Fe/sub 14/B two-phase magnet alloys

Magnetic aftereffect and magnetization process of melt-spun nanostructured /spl alpha/-Fe/Nd/sub 2/Fe/sub 14/B two-phase alloys have been investigated. The heat-treated flakes composed of nanoscaled grain size show enhanced magnetic properties due to the intergranular exchange interaction similar to the exchange-spring behavior. The magnetization shows a logarithmic decay with the elapsed time in a steady field, being consistent with the Barbier plot and analytical results. The activation volume increases with increasing content of soft iron. The dc-demagnetization remanence data elucidate the irreversible demagnetization process. The soft iron phase, being responsible for reversible magnetization (M/sub rev/), exchange-couples with the hard phase and lessens the M/sub rev/.