Preparation of Mn-Zn nanoferrite by mechanical alloying

Full text: In this research Mn-Zn nanoferrite (MnxZn1-xFe2O4;X=0.3,0.5,0.7)were prepared by mechanical alloying of a mixture of 2 single phase ferrites, MnFe2O4 and ZnFe2O4. First, ZnFe2O4 and MnFe2O4 were obtained by conventional ceramic technique. In this technique a mixture of related raw materials(ZnO and MnO2 from merck company and Fe2O3 domestic source) was first mixed and calcined at 1100 C for 3h in air. The starting materials used to prepare Mn-Zn nanoferrite were MnFe2O4 and ZnFe2O4 mixed in the ratio appropriate for the reaction: xMnFe2O4+(1-x)ZnFe2O4 MnxZn1-xFe2O4 and milled at different times in SPEX8000M mixer/mill. XRD investigations was used to study the phase formation of the as-milled mixed ferrite. Using XRD patterns and Scherrer's formula, mean crystallite size of the single phase samples were calculated and were in the 10-20 nm. Saturation magnetization(Ms) of the powders was measured at room temperature by a very sensitive home made permeameter. The measured Ms values show that they are smaller than the Ms values associated with the same compound prepared by conventional ceramic technique. The decrease is due to the surface effect in nanoparticles, which can be explained on core-sell model. (authors)