Thermal aging effects on magnetisation reversals in a pre-deformed Fe-1wt%Cu alloy studied via first-order reversal curves

We report the results of measurements of first-order reversal curves (FORCs) for a thermally aged Fe-1wt%Cu alloy with different levels of rolling reduction. We find that the FORC distribution has a peak at high switching and interaction fields for samples with high rolling reductions and that this peak rapidly shifts towards lower fields after aging, which is associated with a narrowing of the peak. Conversely, after aging for more than 10,000 min, the peak exhibits an additional shift towards higher fields, which is associated with a broadening of the peak. These results indicate that both the microstructural homogeneity and the material hardening changes during thermal aging in a competitive way due to recovery and Cu precipitation, which is consistent with small-angle and wide-angle neutron scattering data.