Mechanical spectroscopy of Mn–Zn ferrite

The shear modulus and internal friction in polycrystalline manganese-zinc ferrite are measured as a function of temperature between 20 and 500 °C, by using a torsion inverted pendulum. Curves of modulus versus temperature show a phase transition near the Curie temperature (TC). Three internal friction peaks R1, R2 and R3 are observed on the curves of internal friction versus temperature. The peak R1 in ferrimagnetic state is discussed in interaction of domain walls with point defects. The peak R2 below the TC is attributed to viscous motion of domain walls. The peak R3 could be ascribed to the exchange of cations and their vacancies, and clustering Mn3+ ions on octahedral sites.