Nagwa Okasha

In this study, Spinel nano ferrite (MFe2O4) ferrite powders were prepared by auto-combustion reaction. Nanoparticles have been synthesized by sol-gel method using citric acid as chemical catalyst while graphene Oxide prepared using Hammer technique and the starting raw materials as graphite powder. A straightforward procedure for creating magnetic nanoparticles coated with graphene oxide was disclosed (M = Zn. metal sites). Graphene oxide (GO) also causes the composite to have nanoparticles with a smaller dimensional size (3.61 nm). The structural identification of the samples was carried out using X-ray Diffraction (XRD), were used to characterize the structure of MFe2O4; the average crystallite size ranges from 26.7 to 35.1 nm. Transmission electron microscope (TEM), selected area electron diffraction (SAED) and IR spectra, which commonly had diameters between 25 and 120 nm. VSM was used to measure the magnetic characteristics coercivity (Hc) and saturation magnetization (Ms). Our samples are soft magnetic materials, as evidenced by the low coercivity of the magnetization curves. ZnFe2O4 nanoparticles and ZnFe2O4/GO 50% had saturation magnetizations (Ms) of 2.7902 and 1.4546 emu/g, respectively. According to the findings, MFe2O4 has a spinel-like structure with high porosity and surface area as well as significant saturation magnetization, making it a promising contender for a number of applications.

We report a comparative study of rare-earth ions substituted Bi0.6Sr0.4FeO3(BSFO) crystal for; BSFO, Bi0.57Sr0.4Y0.03FeO3, Bi0.57Sr0.4Nd0.03FeO3, Bi0.57Sr0.4Ce0.03FeO3, and Bi0.57Sr0.4La0.03FeO3, respectively. The samples were successfully synthesized using flash autocombustion reaction. X-ray diffraction analysis reveals that the crystal structure is rhombohedral and a clear hexagonal grain growth habit is seen by FESEM microstructure. The doping of BSFO improved the magnetic properties specially Y3+, Nd3+ ions. While Ce3+ improved the electrical conductivity. We argue that the addition of RE is likely to suppress the spiral spin modulation and at the same time increase the canting angle which favors the enhanced ferromagnetism.