A series of
Al substituted
Ni spinel ferrites with the empirical formula , where
x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared by conventional ceramic double sintering method. DC electric properties and initial permeability ( ) were carried out for the prepared series of samples from room temperature to well beyond the Curie point temperature ( ). The thermal behavior of the DC electric conductivity for the prepared samples indicated that they act as semiconducting materials. On the other hand, DC electric conductivity is greatly affected when the ions are increased. The DC electrical conductivity results were interpreted in terms of electron hopping model. The calculated activation energy in the ferrimagnetic region was less than that in paramagnetic region. The initial permeability showed constant values from room temperature to , then it decreased sharply. The Curie temperature was determined from DC electrical properties and initial permeability. was found to decrease with increasing of
ions
