Mittuniversitetet

Nanoferrites having composition Mn_xMg_1−xFe₂O₄(x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) are synthesized by a low-temperature combustion method. The particle size measured from transmission electron microscopy and x-ray diffraction (XRD) patterns confirms the nanosized dimension of the as-prepared powder. From the analysis of XRD data with Scherrer's formula, the average crystallite size ranges from 23 to 33 nm and the lattice parameter ranges from 8.385 to 8.468 Å. Substitution of Mn²⁺ in MgFe₂O₄ causes an increase in the lattice constant, and this moderately distorts the lattice. Magnetic properties such as magnetization (M_s), coercivity (H_c) and remanence (M_r) with increasing Mn²⁺ concentration are studied at room temperature by a vibrating sample magnetometer. Substitution of Mn²⁺ for Mg²⁺ increases M_s from 34.5 to 54.5 emu g⁻¹ and decreases H_c from 51.0 to 45.0 Oe. The results imply that the low-temperature combustion method is an efficient route for synthesis of nanoferrites without any extra calcination step. The as-prepared Mg–Mn ferrites are suitable for memory and switching circuits in digital computers.