Fabrication and temperature-dependent magnetic properties of one-dimensional multilayer Au–Ni–Au–Ni–Au nanowires

• Published in: Journal of solid state chemistry 2014-02, Vol.210 (1), p.116-120
• Main Authors: Ishrat, S., Maaz, K., Lee, Kyu-Joon, Jung, Myung-Hwa, Kim, Gil-Ho
• Format: Article
• Language: English
• Subjects: ALUMINIUM OXIDES; ANISOTROPY; COERCIVE FORCE; Cross-disciplinary physics: materials science; rheology; ELECTRODEPOSITION; Electrodeposition, electroplating; Exact sciences and technology; FABRICATION; FERROMAGNETIC MATERIALS; Ferromagnetism; Gold; HYSTERESIS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Law; Magnetic measurements; MAGNETIC PROPERTIES; MAGNETIZATION; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Multilayers; Nanoscale materials and structures: fabrication and characterization; Nanostructured materials; Nanowires; Nickel; Other topics in nanoscale materials and structures; Physics; Porous materials; granular materials; QUANTUM WIRES; SCANNING ELECTRON MICROSCOPY; Segments; Specific materials; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION; X-RAY SPECTRA
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2013.11.005

Multilayer Au–Ni–Au–Ni–Au nanowires with a controlled diameter of ~100nm were synthesized by electrochemical deposition in porous alumina templates. The length of each Ni-segment was controlled up to ~230nm, while the length of the Au segment sandwiched between two Ni segments was ~180nm. X-ray diffraction patterns and energy-dispersive X-ray spectra confirmed the formation of purely crystalline nanowires. The magnetic properties of the multilayer Au–Ni–Au–Ni–Au nanowires were investigated in the temperature range 2–300K. Room-temperature magnetic hysteresis confirmed the ferromagnetic nature of the nanowires. The plot of coercivity as a function of temperature (from 2 to 300K) followed law applicable for ferromagnetic nanostructures. The magnetization tended to increase as the temperature decreased, following the modified Bloch's law similar to ferromagnetic nanoparticles. (a) SEM image of Au–Ni–Au–Ni–Au nanowire with 230nm Ni segment length and 180nm Au sandwiched between Ni segments (b) Kneller's law (c) Bloch's law [Display omitted] •Electrochemical fabrication of Au–Ni–Au–Ni–Au nanowires in alumina templates.•Formation of beadlike structure of Ni segments.•Coercivity versus T follows Kneller's law for ferromagnetic materials.•Magnetization as a function of temperature follows the modified Bloch's law.