Fig. 7: Field-dependent magnetic properties of irregularly shaped magnetite grains and the impact of shape anisotropy in various field directions.

Examples of magnetic hysteresis (a, c), backfield curves (b, d), and their parameters (for magnetite) are shown. The grey dots represent the field-dependent data, and the red curves depict their averages. Notably, for both types of simulated experiments, different field directions result in distinct curves as a result of the grain’s shape anisotropy. The particles situated at the upper side of the backfield curves (b, d) correspond to the LEM states obtained at zero field. Here, we highlight how the Mr of these states might differ from the Mrs of magnetic hysteresis (compare the Mrs values within the boxes in (a) and (c) with the respective Mr values within the grains).