Synthesis, Structural, and Magnetic Properties of Nanocrystalline/Nanosized Manganese-Nickel Ferrite–${\rm Mn}_{0.5}{\rm Ni}_{0.5}{\rm Fe}_{2}{\rm O}_{4}$

Abstract

The nanocrystalline/nanosized mixed manganese–nickel spinel ferrite ${\rm Mn}_{0.5}{\rm Ni}_{0.5}{\rm Fe}_{2}{\rm O}_{4}$ was successfully synthesized by the classical ceramic method followed by mechanical milling. The refinement of the crystallite size is obtained by increasing the milling time up to 120 min. The particles size distribution performed on the milled powder showed a fine ferrite powder. The Neel temperature of ${\rm Mn}_{0.5}{\rm Ni}_{0.5}{\rm Fe}_{2}{\rm O}_{4}$ decreases by increasing the milling time as a result of the structural disorder and it is larger when compared with the manganese ferrite one and lower when compared with the nickel ferrite one. The saturation magnetization of the spinel structure was found to be 2.42 $\mu_{B}$ and it is close to the theoretical one 2.5 $\mu_{B}$ . The saturation magnetization and spontaneous magnetization decrease by increasing milling time. The spontaneous magnetization is reduced more drastically when compared with the saturation magnetization. One of the major causes is assumed to be the spin canted effect induced at the particles surface by milling process.