Dielectric and magnetic investigations of mixed cubic spinel Co-ferrites with controlled Mg content

High temperature frequency dependent dielectric properties, and room temperature magnetic behavior of mixed ferrites with controlled content of Mg in Co _1−xMg _xFe ₂O₄(x=0.0,0.1,0.3,0.5,0.7,0.9 and 1.0) compositions are studied. Single phase spinel structure with cubic symmetry, lattice parameters, crystallite size, magnetic and dielectric properties were substantiated with x-ray diffractometer, transmission electron microscope, vibrating sample magnetometer and impedance analysis, respectively. Due to interfacial polarization, dielectric behavior of all the compositions shows dispersion with increase in frequency. The dielectric data was investigated by comparing the tangent loss and electric modulus for assigning the type and mechanism of dielectric relaxation. Temperature dependent dielectric constant, tangent loss and AC conductivity increase due to thermal activation of charge carriers and drift mobility. Furthermore, room temperature weak ferromagnetic behavior is observed due to the incorporation of non-magnetic Mg ions.