Effect of processing parameters on the magnetic properties of Ni0.8Zn0.2Fe2O4

Polycrystalline nickel-zinc ferrite powder has been obtained by chemical co -precipitation, involving the corresponding metal nitrates and sodium hydro xide under the different processing parameters for precipitation from those reported in our earlier paper [1, Anilkumar rt al., Mater Lett, 27(1996) 2 93]. The precipitate, when dried at 80 degreesC in air shows cubic ferrite with lower values for Ms approximate to 17.7emu/g (Ms approximate to 44 emu /g as reported in the earlier paper cited above). Different modes of drying such as IR drying, microwave drying do not improve Ms values. On the other hand, Ms value improves substantially when the precipitate is further proc essed hydrothermally. When calcined at 1200 degreesC/4h in air, all the sam ples reach 96-100% of the saturation value (Ms approximate to 77 emu/g). Al l these experimental results (XRD, VSM) are analyzed in terms of the micros copic inhomogeneity (structural and chemical) of the precipitated and calci ned samples.