Magnetic properties of the Ni–Cu–Zn system doped with magnesium oxide

Abstract A series of ferrite samples, Ni 0.1 Cu 0.2 Mg x Zn 0.7− x Fe 2 O 4 , ( x =0.00, 0.15, 0.25, 0.35, 0.45, 0.55 and 0.70) has been prepared by the standard ceramic technique, sintered at 1200 °C for 2 h, and their crystalline structures were investigated by using X-ray diffraction. The IR spectra and the ESR spectra analysis have been studied. DC electrical resistivity, thermoelectric power, charge carriers concentration and charge carrier mobility have been calculated at different temperatures. The value of dc electrical resistivity reach minimum at x =0.35 and above this value the electrical resistivity start to increase. It is noticed that thermoelectric power α for the “Ni–Cu–Zn” system exhibits a positive sign indicating the majority carriers are holes without excluding the presence of electrons. Saturation magnetization M s for the “Ni–Cu–Zn” system was calculated from M – H loop. It is noted that Ms decreases with Mg content up to x =0.55 and rapidly decrease above x >0.55 for the “Ni–Cu–Zn” system.