title: Synthesis of superparamagnetic bare Fe₃O₄ nanostructures and core/shell (Fe₃O₄/alginate) nanocomposites.
abstract: In this article we report about the synthesis of superparamagnetic bare Fe3O4 nanostructures and core/shell (Fe3O4/alginate) nanocomposites by simple low-temperature based method at pH values 5, 9, and 14. The structural morphology and magnetic behavior of Fe3O4 nanostructures and core/shell (Fe3O4/alginate) nanocomposites (Fe3O4/alg NCs) have been investigated by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), ultraviolet-visible (UV-vis) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM). The particle size was calculated by TEM measurements and it turns out to be ∼10 nm and ∼14 nm for bare Fe3O4 nanoparticle and Fe3O4/alg NCs with core/shell structure, respectively. The magnetic properties of the synthesized products were found to be function of pH at which the synthesis has been done. The synthesized Fe3O4 nanoparticle and Fe3O4/alg NCs were found to be superparmagnetic in nature at room temperature. We observed that the value of saturation magnetization in case of Fe3O4/alg NCs decreases by increasing the pH value.
authors.affiliation: Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004, India; Department of Physics, Dehradun Institute of Technology (DIT) School of engineering, Greater Noida 248001, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Srivastava
authors.affiliation: Department of Science and Technology Centre on Biomolecular Electronics Biomedical Instrumentation Section, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012, India.
authors.forename: Jay
authors.initials: J
authors.lastname: Singh
authors.affiliation: Electron Microscope Facility, Department of Anatomy, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Madhu
authors.initials: M
authors.lastname: Yashpal
authors.affiliation: Department of Chemistry, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004, India.
authors.forename: Dinesh Kumar
authors.initials: DK
authors.lastname: Gupta
authors.affiliation: Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Mishra
authors.affiliation: Department of Chemistry, School of Basic and Applied Sciences, Galgotias University, Gautam Budha Nagar 201306, India.
authors.forename: Shipra
authors.initials: S
authors.lastname: Tripathi
authors.affiliation: Department of Physics, Motilal Nehru National Institute of Technology, Allahabad, Allahabad 211004, India.
authors.forename: Animesh K
authors.initials: AK
authors.lastname: Ojha