Giant magnetodielectric effect and magnetic field tunable dielectric resonance in spinel MnZn ferrite

Abstract

The sensitive response of the dielectric permittivity under the application of magnetic fields in Mn0.60 Zn0.40 Fe 2.12O4+δ polycrystalline ferrite is presented. A magnetic field of 3.5 kOe induced a giant magnetodielectric { MD= [ε′ (H) - ε′ (0)]/ε′ (0) } response, of 1800% at f=7 MHz, at room temperature. The ferrite exhibits a large magnetic field-induced frequency response of 180 Hz/Oe. We suggest that this effect arises primarily from a spin-dependent space charge polarization mechanism in response to the application of dc magnetic fields. © 2009 American Institute of Physics.