OPTIMUM FIRING TEMPERATURES FOR FABRICATION OF FERROMAGNETIC Mn0.85Zn0.15 Ni0.15Fe2O4 CERAMICS VIA THE SOLID-STATE COMBUSTION TECHNIQUE

In this research, optimum firing temperatures for the fabrication of ferromagnetic Mn0.85Zn0.15Ni0.15Fe2O4 (MZNF) ceramics were investigated. MZNF ceramics were prepared via the solid-state combustion method using glycine as fuel. All samples were calcined in the temperature range of 1,000-1,150ºC for 2 h and sintered between 1,200 and 1,275ºC for 2 h. Pure MZNF powders were obtained by calcining at 1,150°C for 2 h. Increasing the sintering temperature improved the cubic spinel structure. The average particle size and the average grain size tended to increase from 0.38 to 1.61 µm and 6.38 to 8.15 µm, respectively, with an increase in the firing temperatures. The dielectric constant at room temperature (εr) of the samples increased with increased sintering temperatures. Density and saturated magnetization (Ms) of the ceramics increased from 4.74 to 4.87 g/cm3 and 63.40 to 84.67 emu/g, respectively, when the sintering temperature increased from 1,200 to 1,250°C, and then those parameters decreased as the temperature went above 1,250°C. At the optimum sintering temperature (1,250°C), MZNF ceramics exhibited good crystallinity, a packed microstructure, the highest density (4.87 g/cm3), good dielectric properties and excellent ferromagnetic properties (Ms = 84.67 emu/g and Hc = 1.42 Oe).