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Magnetic hybrids with exceptional magnetic and optical properties have emerged as promising materials for diverse applications. In the present work, magnetite (Fe3O4)-functionalized graphene oxide (GO) was synthesized using a facile in situ coprecipitation synthesis method. The in situ formation of Fe3O4 nanoparticles in the presence of GO led to the self-assembly of GO sheets into nanoscrolls. The structural and morphological properties of the nanoscrolls were evaluated. The optical properties were studied using UV-Vis absorbance spectroscopy. Magnetic response assessment by vibrating sample magnetometer confirmed that Fe3O4–GONS had a good superparamagnetic property with maximum saturation magnetization of 54.4 (± 0.5) emu gm−1. The superparamagnetic blocking temperature of the FGO 1 sample was evaluated by temperature-dependent magnetization studies. The in vitro cytotoxicity of the prepared nanocomposites was investigated using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay on a fibroblast L929 cell line. The cell viability studies reveal that all the Fe3O4–GO nanohybrids exhibit excellent cell viability (above 80%) compared to that of the control sample. It is worth noting that the magnetic functionalization of GO with Fe3O4 and the scroll structure is a way to enhance the biocompatibility. This work suggests the promise of using multifunctional Fe3O4–GO hybrids in biomedical applications. [ABSTRACT FROM AUTHOR]

Spinel-structured nickel ferrite has been prepared using co-precipitation method. The ferrite particles prepared were characterized using XRD, FTIR, and TEM and were confirmed to be in the nano-regime. Natural rubber composites were prepared with different loadings of nickel ferrite like 5, 15, 25, 50, and 75 (in part per hundred rubber, phr). The mechanical, swelling, and magnetic properties were analyzed using the standard methods. Dielectric measurements show that permittivity decreases with increase in frequency and increases with increase in ferrite loading. Tan delta value also was found to increase with filler loading which may be attributed to the presence of interfacial polarization. [ABSTRACT FROM AUTHOR]

Novel magnetoelectric (ME) CuFe 2 O 4 @BaTiO 3 core-shell and (1- x )BaTiO 3 - x CuFe 2 O 4 ( x = 0.1, 0.3, 0.5, 0.7 and 0.9) composites were prepared by two step sol-gel and a sol-gel followed by a solid state reaction respectively. Crystal structure and microstructure of the samples were examined using X-ray diffraction (XRD) and transmission electron microscopic (TEM) techniques. The ferroelectric and magnetic properties of the materials were confirmed by polarization versus electric field (P-E) and magnetization versus magnetic field (M-H) measurements respectively. To determine the coupling between ferroelectric and magnetic orderings, ME coupling studies were performed using a lock-in amplifier setup. The highest value of the ME coupling coefficient (α) was noticed for the CuFe 2 O 4 @BaTiO 3 core-shell (α = 22.5 mV cm −1 Oe −1 ) sample. Superior ME coupling behavior in the core-shell material is due to better connectivity between the ferroelectric and magnetic phases. The optical measurements indicate the possibility of easy manipulation of the band gap over a range of energies by mere control of the molar ratio of the phases. The smart architecture enables CuFe 2 O 4 @BaTiO 3 to be a highly promising material for the design of devices based on ME multiferroics. [ABSTRACT FROM AUTHOR]