Crystallographic and Magnetic Properties of MnxFe3-xO4Powders

Abstract

<TEX>$Mn_xFe_{3-x}O_4$</TEX> powders have been fabricated by using sol-gel methods; their crystallographic and magnetic properties were investigated by using X-ray diffraction, scanning electron microscopy, M<TEX>$\ddot{o}$</TEX>ssbauer spectroscopy, and vibrating sample magnetometer. The <TEX>$Mn_xFe_{3-x}O_4$</TEX> ferrite powders annealed at <TEX>$500^{\circ}C$</TEX> had a single spinel structure regardless of the <TEX>$Mn^{2+}$</TEX>-doping amount and their lattice constants became larger as the <TEX>$Mn^{2+}$</TEX> concentration was increased. Their Mossbauer spectra measured at room temperature were fitted with 2 Zeeman sextets due to the tetrahedral and octahedral sites of Fe ions, which made them ferrimagnetic. The magnetic behavior of <TEX>$Mn_xFe_{3-x}O_4$</TEX> powders showed that the <TEX>$Mn^{2+}$</TEX>-doping amount made their saturation magnetization increase, but there were no severe effects on their coercivities. The saturation magnetization of the <TEX>$Mn_xFe_{3-x}O_4$</TEX> powder varied from 38 emu/g to 70.0 emu/g and their minimum coercivity was 111.1 Oe.