X-ray and bulk magnetic properties of the Ni-Zn ferrite system

Compositions having the general formula Ni1-xZnxFe2O4 with x=0.30, 0.35, 0.40: 0.45 have been sintered at 1100, 1150, 1200, and 1240 degrees C to attain different microstructures. The grain size D for a particular composition increases linearly with increasing sintering temperature. The lattice parameter a and magnetization M(s) are seen to be invariant with the change in sintering temperature. The coercive force H-c and the remanent ratio R=M(r)/M(s) are seen to depend on the sintering temperature and hence on D. a and M(s) are found to increase with the increase of the Zn content. whereas H-c values show a decreasing trend with the Zn content. The compositional, thermal, and microstructural variation of hysteresis parameters like M(s), H-c, and R=M(r)/M(s) reveal that magnetic grains in the compositions investigated are of multi-domain type. This result is supported by ac susceptibility data.