Low temperature synthesis of nanosized Mn_1−x Zn _x Fe₂O₄ ferrites and their characterizations

Abstract

Nanosized Mn_1−x Zn _x Fe₂O₄ (x = 0, 0·1, 0·3, 0·5, 0·6, 0·7, 0·9) mixed ferrite samples of particle size < 12 nm were prepared using the co-precipitation technique by doping the Zn²⁺ ion impurities. Autoclave was employed to maintain constant temperature of 80°C and a constant pressure. The X-ray analysis and the IR spectrum analysis were carried out to confirm the spinel phase formation as well as to ascertain the cation distribution in the ferrite samples. This clearly points to the fact that the Zn²⁺ ion’s presence is not restricted to A-site alone for some of the Mn-Zn ferrite series. The real part of a.c. susceptibility measurements clearly indicated the superparamagnetic behaviour of the ferrite samples. There is a systematic decrease in the particle size, Curie temperature and magnetization with the increase in the Zn²⁺ ion doping, measured using magneto thermal gravimetric analysis (MTGA) and vibrating sample magnetometer (VSM), respectively. The lattice constant is found to be constantly decreasing till x = 0·6 and beyond this an unusual slight increase in the lattice constant is found.