Kvvmm. Rao et al., DIELECTRIC-DISPERSION IN ALUMINUM-DOPED ZINC MANGANESE FERRITES, Physica status solidi. a, Applied research, 144(1), 1994, pp. 235-241
The dielectric constant epsilon, loss tan delta, and conductivity sigm
a of aluminium doped zinc-manganese ferrites of general formula Zn0.3M
n0.7Fe2-xAlxO4 (with x values ranging from 0.2 to 1.0) are studied as
a function of frequency, in the range 5 to 500 kHz and in the temperat
ure range 30 to 150-degrees-C. All these samples are found to exhibit
dipolar relaxation effects. The variations in epsilon and tan delta wi
th frequency and temperature are observed to be strongly dependent on
the concentration of aluminium. The results are explained on the basis
of the Verwey mechanism involving hopping of electrons in the spinel
structure.