Synthesis and functional properties of the Ni1−xMnxFe2O4 ferrites

Nanocrystalline Ni1−xMnxFe2O4 (x = 0; 0.17; 0.34; 0.5) ferrite powders were successfully synthesized using the sol–gel combustion method, by using nitrates as cations source and citric acid (C6H8O7) as combustion/chelating agent. The reaction advancement was observed by means of IR absorption spectroscopy, by monitoring two characteristic bands for the spinel compounds at about 600 cm−1 and 400 cm−1, respectively. The as-synthesized powders were characterized by IR spectroscopy, X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The magnetic study shows that the saturation magnetization decreases with increasing the Mn addition, as result of the particle size reduction. The dielectric properties were measured as a function of frequency in the range of 10 Hz to 1 MHz. The real part of permittivity has values of ∼88 at 1 kHz and ∼7 at 1 Hz for x = 0. An increasing dielectric permittivity with increasing the amount of Mn is observed. For all the investigated compositions, both the real and imaginary parts of permittivity decrease with frequency.

► The Ni1−xMnxFe2O4 ferrite ceramics were obtained by gel-combustion method. ► By Mn addition a decreasing of crystallite size was obtained. ► The magnetic and dielectric properties revealed relatively high values of permeability and low values of dielectric permittivity in the range kHz–MHz, which made the ferrite as promising materials for microelectronic applications.