Interaction of magnetic domain walls with microstructural features in spinel ferrites

Lorentz microscopy studies of (Mn, Zn)Fe2O4and LiFe5O8show that grain boundaries, pores, microcracks, stacking faults, and non-magnetic second phase particles act as pinning sites for moving domain walls. Second phase particles, pores, and some grain boundaries also act as favorable sites for reverse domains to be nucleated. In addition, it is observed that domain walls cannot move smoothly as they approach a grain boundary.