جستجوی مقالات مرتبط با کلیدواژه « فریت منگنز » در نشریات گروه « مواد و متالورژی »

Manganese ferrite nanoparticles (NPs) have different applications, especially in medical diagnosis and treatment as well as the biomolecule separation,. In this research, the effects of various parameters such as the pH of reaction solution and the hydrothermal process duration on the synthesis of spinel phase in NPs were evaluated. Crystal structure, chemical composition, morphology and size of synthesized particles were investigated by the X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDS). The XRD results showed that the process duration of 12 h and pH=11 were suitable for the formation of monophase manganese ferrite NPs. The FE-SEM investigations showed that the average size of the synthesized NPs was about 50 nm. Moreover, the EDS analysis showed the presence of about 20% of manganese in the NPs structure. Hydrothermally synthesized manganese ferrite NPs in this researchcould be, therefore, a good candidate for the biomedical application due to their small size and narrow size distribution.

In this work, Mn1-xCoxFe2O4 (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) nanoparticles have been prepared by coprecipitation method. The effects of Co2 substitution on the cation distribution between tetrahedral and octahedral sites in spinel structure, magnetic properties and AC magnetically induced heating characteristics were investigated. The structure and cation distribution characterized by X-ray diffraction and Raman spectroscopy showed the substituted Co2 cations mainly entered to octahedral sites. The particle size of the as-coprecipitated powders observed by scanning electron microscopy decreased with cobalt additions. Magnetic properties of Mn1-xCoxFe2O4 nanoparticles studied by vibrating sample magnetometry showed the highest coercivity and saturation magnetization of 790 Oe and 32.8 emu/g for Mn0.7Co0.3Fe2O4 nanoparticles, respectively. The Mn0.7Co0.3Fe2O4 nanoparticles exhibited the AC heating temperature of 8 °C and specific loss power of 1.4 W/g in comparison with 4 °C and 0.35 W/g for the as-coprecipitated MnFe2O4 powders.

Magnesium-manganese ferrite nanopowders (MgxMn1-xFe2O4, x=0.0 up to 1 with step 0.2) were prepared by coprecipitation method. The as-prepared samples were pressed with hydrolic press to form a pellet and were sintered in 900, 1050 and 1250˚C. Scanning Tunneling Microscope (STM) images showed the particle size of powders about 17 nm. The X-ray patterns confirmed the formation of cubic single phase spinel structure in samples sintered at 1250˚C. Substituting Mg2 with Mn2 in these samples, the lattice parameter decreased from 8.49 to 8.35Å and magnetization saturation decreased from 74.7 to 21.2emu/g. Also, coercity (HC ) increased from 5 to 23Oe and Curie temperature (TC ) increased from 269 to 392˚C. Samples with x= 0.2, 0.4, 0.6 sintered at 1250 ˚C, because of their magnetic properties, can be recommended for hyperthermia applications and for phase shifters.