## 3 Results and Discussions
### The Effect of Sintering Temperature on the Crystal Phase and the Magnetic Properties  
Figure 5a shows the XRD diagram (sintering in an air atmosphere, an increase in temperature of 5 \({}^{\circ}\)C/min, and then a constant temperature for 2 h, followed by cooling in a furnace) for [Mn\({}_{0.54}\)Zn\({}_{0.46}\)]Fe\({}_{2}\)O\({}_{4}\) that is sintered at different temperatures. It is seen that when the sintering temperature is increased, the XRD diffraction peak increases in height, so the strength of the ferrite increases. An increase in the sintering temperature produces particle with a greater diameter. When the calcination temperature is 700 \({}^{\circ}\)C, the XRD diffraction peak shows slight amounts of \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\). When the sintering temperature is increased to 800 \({}^{\circ}\)C, the diffraction peak for \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) is larger. This demonstrates that in an air atmosphere, when the sintering temperature exceeds 600 \({}^{\circ}\)C, \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) is generated immediately and there is a decrease in the saturated magnetization for Mn-Zn ferrite. The value for the average particulate diameter for [Mn\({}_{0.54}\)Zn\({}_{0.46}\)]Fe\({}_{2}\)O\({}_{4}\) that is sintered in an air atmosphere at different temperatures is calculated using the diffraction peak. The value is 11.50 nm for unsintered material, and an increase in the sintering temperature produces an increase in the average particulate diameter. At temperatures greater than 600 \({}^{\circ}\)C, decomposition occurs because Mn is oxidized. However, the average particulate diameter for \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) increases when the sintering temperature is increased, so even if there is decomposition because Mn is oxidized, the average particulate diameter increases until the sintering temperature is 800 \({}^{\circ}\)C, at which temperature the average particulate diameter is 69.20 nm. Figure 5b shows the effect of sintering temperature on the magnetic properties, using the hysteresis curve for [Mn\({}_{0.54}\)Zn\({}_{0.46}\)]Fe\({}_{2}\)O\({}_{4}\) at different sintering temperatures. A sintering temperature of 600 \({}^{\circ}\)C results in the greatest value for saturated magnetization. When the sintering temperature exceeds 600 \({}^{\circ}\)C, the saturated magnetization begins to decrease. A sintering temperature of 800 \({}^{\circ}\)C gives a saturated magnetization of 2.57 M (emu/g), which is less than the value for unsintered ferrite. When the temperature is increased, there is an increase in thermal vibration in the lattice. The binding energy for the oxygen atoms also decreases, so these escape [2]. When the sintering temperature exceeds 600 \({}^{\circ}\)C, the amount of \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) in the crystal phase is increased (\(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) is also called hematite, which is not magnetic [24; 25]). If sintering is performed in a N\({}_{2}\) atmosphere, a reducing environment is formed within the furnace. The results for the magnetic flux for [Mn\({}_{0.54}\)Zn\({}_{0.46}\)]Fe\({}_{2}\)O\({}_{4}\) at different sintering temperatures show that the magnetic flux at a temperature of 500 \({}^{\circ}\)C is 96.91 gauss/g. An increase in the sintering temperature produces an increase in the magnetic flux. When the temperature is 600 \({}^{\circ}\)C, there is a maximum value of about 211.71 gauss/g and the value then begins to decrease for higher temperatures,  
Figure 5: The effect of the sintering temperature in an air atmosphere on **(a)** the crystal phase and **(b)** the magnetic properties. because when sintering is performed in an air atmosphere, the Fe atoms in [Mn\({}_{\rm x}\)Zn\({}_{\rm 1-x}\)]Fe\({}_{\rm 2}\)O\({}_{\rm 4}\) are thermally disassociated into \(\alpha\)-Fe\({}_{\rm 2}\)O\({}_{\rm 3}\).