Magnetization behaviour in exchange-coupled -Fe

A comparative study has been performed concerning the magnetization behaviour of single-phase and two-phase exchange-coupled . Measurements of reversible and irreversible magnetization and magnetic viscosity have been performed on nanocrystalline samples prepared by mechanical alloying and subsequent heat treatment. Measurements of reversible susceptibility show that the large reversible magnetization of the two-phase material may be attributed entirely to the contribution of the soft phase. It is shown that the two-stage reversal process observed during de-magnetization of the two-phase material is associated with the transition from reversible to irreversible magnetization of the exchange-coupled soft phase. Measurements of magnetic viscosity show that no time-dependent changes occur in the soft phase except when associated with reversal of the hard phase.