Effects of magnetic field on fracture toughness of manganese-zinc ferrite ceramics

Effects of magnetic field on the fracture toughness of magnetic ceramics were experimentally investigated by the use of the single-edge-notch-beam (SENB) specimens of three kinds of manganese-zinc ferrite ceramics with different permeability. Results indicate that there is no significant change in the measured fracture toughness of the Manganese-Zinc Ferrite ceramics in the presence of the magnetic field. Furthermore, the crack lengths caused by the Vickers' indentation on the manganese-zinc ferrite ceramics show that the fracture toughness in the magnetic field direction is almost identical to that in the direction perpendicular to the magnetic field. This reveals that the polycrystalline ceramic still exhibits isotropic fracture behavior after magnetization. Finally, a qualitative explanation is given in terms of a small-scale magnetic saturation model.