Acoustic Losses in Single Crystals of Mn–Zn Ferrite and Titanium Substituted Mn–Zn Ferrites

Abstract

The acoustic losses in single crystals of Mn–Zn ferrite (Mn 0.53 Zn 0.35 Fe 2.12 O 4 ) and Mn–Zn ferrites substituted by titanium for three levels at 0.06, 0.07 and 0.09 per formula unit were studied at temperatures between 300 and 600 K by longitudinal vibration of 125 kHz. A loss-peak was observed at 479 K in the Mn–Zn ferrite along the [110] direction with and without an external magnetic field. This peak was attributed to the exchange motions between cations and their vacancies on the octahedral sites, and the activation energy for a vacancy is evaluated to be 0.81 eV. A similar loss-peak was observed for every titanium substituted Mn–Zn ferrite. The height of the peak increased and its temperature decreased with the increase in titanitun content. This peak dissolved into two relaxational loss-peaks due to exchanges between cations and the vacancies, which for one of the peaks the vacancies are induced by the titanium substitutions, and for the other they are thermally induced on the octahedral sites.