Large scale re-producible synthesis and magnetic properties of Ni/graphite core-shell nanostructured materials

• Published in: Journal of magnetism and magnetic materials Vol. 501; p. 166444
• Main Authors: Saini, Lokesh, Kumar Patra, Manoj, Dixit, Ambesh
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2020; Elsevier BV
• Subjects: Annealing; Blocking temperature; Core-shell; Core-shell structure; Ferromagnetism; Functional materials; Graphite; Magnetic measurement; Magnetic properties; Magnetic saturation; Magnetism; Magnetization; Medical materials; Microwave absorption; Nanomaterials; Nanoparticles; Nanostructured materials; Nickel; Physical properties; Process parameters; Room temperature; Structural analysis; Superparamagnetism; Synthesis; Temperature dependence; Temperature distribution; Nanoparticles; Blocking temperature; Superparamagnetism; Magnetization; Core-shell
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2020.166444

[Display omitted] •Design of scalable synthesis process with highly reproducible Ni/graphite core/shell nanoparticles.•Variable size of nanoparticles by controlling the annealing temperature.•Size of Ni core is less than bulk Ni single ferromagnetic domain for all samples.•Superparamagnetic properties with variable blocking and saturation magnetization values.•Maximum magnetic moment ~25 emu g−1 for the largest core/shell particle. We designed an experimental set-up and optimized the process parameters for large scale synthesis (250 g) of low density nickel core metal with graphitic carbon shell as functional nanomaterial with highly reproducible physical properties. Structural characterization reveals formation of nano-core FCC Ni metal ~40 nm with ~7 nm thick graphitic shell after annealing at 850 °C. Room temperature field dependent magnetic (M−H) measurement reveals significant saturation magnetization in the sample even with non-magnetic graphite shell. The structural and magnetic properties are compared with small-scale batch synthesis (10 g), reported earlier. The temperature-dependent magnetic measurements suggest that Ni/graphite core-shell samples, annealed at 550 °C, and 700 °C are superparamagnetic, whereas sample annealed at 850 °C is ferromagnetic. The developed synthesis set-up is simple, environment friendly, and cost-effective. Further, to cater the end use applications of such materials for industrial, bio-medical and microwave absorption, the reported method may be further scaled up for large production.