Reversible and irreversible magnetization processes in materials displaying two-dimensional hysteresis

We have investigated the vector hysteresis properties of Co-based disk-shaped amorphous specimens, with in-plane macroscopic uniaxial anisotropy. The samples were subjected to a field Ha applied in the sample plane along a direction making with the easy axis an angle θHaθHa ranging between 0° and 90°. The role played by reversible and irreversible magnetization processes is studied along the first magnetization curve and the major loop. We have identified the parameters of a vector model based on the Stoner–Wohlfarth approach, and accounting for spin rotations and domain wall assisted processes. Finally, we have demonstrated the possibility of reproducing the whole vector hysteresis behavior from the measurement of the hysteresis loops for θHa=0∘θHa=0∘ and 90°.