Preparation and Magnetic Properties of MnFe2O4 Octahedral Microcrystals

Abstract

MnFe 2 O 4 octahedra have been prepared by reaction of Mn 2+ ions and Fe 3+ in alkaline condition via heat treatment of the coprecipitation product. The as-prepared powders were characterized in detail by conventional techniques such as powder x-ray diffraction; field emission electron microscopy and transmission electron microscopy. Vibrating sample magnetometer was used to determine the magnetic properties at room temperature. The results show that the MnFe 2 O 4 octahedra were single crystals with cubic jacobsite structure and a size distribution from 0.8 to 1.0 lm. The octahedra obtained at 1100 and 1200°C exhibited a ferromagnetic behavior with the coercive force (H c ) value of 49.03 and 39.23 Oe, saturation magnetization (M s ) value of 42.93 and 47.98 emu/g and remanent magnetization (M r ) value of 2.16 and 2.55 emu/g, respectively. It is indicated that the heat treatment temperature has a significant effect on the formation of the jacobsite structure. Furthermore, a possible mechanism was also proposed to account for the growth of these products.

Removal of Reactive Dyes in Textile Effluents by Catalytic Ozonation Pursuing on-Site Effluent Recycling

“…This inconsistent shape also found in some crystals prepared over base substrates [32]. The crystal shape of MnFe 2 O 4 has been studied previously as a function of calcination temperature, at temperatures ranging from 900–1200 °C [33]. The present nanooctahedral shape obtained was in line with that prepared after calcination at 1100 °C.…”

The Preparation and Characterization of MnFe2O4-Decorated Expanded Graphite for Removal of Heavy Oils from Water

“…It can be seen from Figure 3B that the saturation magnetization of EG is close to zero. With additional magnetic octahedralMnFe 2 O 4 particles into EG, the value of saturation magnetization was found to be 16 emu/g, which is much lower than the theoretical magnetism value of bare MnFe 2 O 4 reported in the literature [23,24]. This is given that the MnFe 2 O 4 wrapped by non-magnetic graphite sheets presenting as antiferromagnetic layers on the surface may result in a decrease in magnetism of EG-MnFe 2 O 4 .…”

“…The emergence of new peaks with the addition of MnFe 2 O 4 into EG was also observed in the XRD spectrum. For instance, the appearance of peaks at 2θ = 30.10°, 35.50°, 43.10°, and 57.00°, respectively, stands for the (220), (311), (400), and (511) reflections of octahedral MnFe 2 O 4 [23,24], indicating the successful incorporation of magnetic particles to graphite layers. Additionally, the disappearance of peak at 44.32° and 54.54° in the XRD spectrum of modified EG indicated that graphite sheets were further expanded during the synthesis process with heating at 700 °C.…”

Mn3−xFexO4 Hollow Nanostructures for High‐Performance Asymmetric Supercapacitor Applications

“…Moreover, manganese and iron ions are natural abundance and less toxicity, which are suitable for practical applications. [15,16] Kuo et al reported MnFe 2 O 4 /carbon black composite was synthesized by a co-precipitation method, which exhibits superior cycling stability as excellent electrode material in supercapacitor. [17] Besides, the micromorphology of electrode materials is an important factor that decides the electrochemical performance of a supercapacitor, which is beneficial to improve electrochemical performance.…”

“…Ternary manganese ferrite with a multi‐oxidation state promotes electrochemical reactions, enabling them high specific capacitance. Moreover, manganese and iron ions are natural abundance and less toxicity, which are suitable for practical applications [15,16] . Kuo et al.…”