Synthesis of Cobalt/Gold Bimetallic Particles with Porous Flake-Like Nanostructures and Their Magnetic Properties

Porous cobalt gold nanostructures with Au nanoflakes covering the top of their cobalt cores were synthesized through facile galvanic replacement reaction with the assistance of ultrasonic bath. The average thickness of the nanoflakes was around 50 nm–60 nm. The magnetic properties of the bimetallic particles were measured after galvanic replacement reaction. Compared with the as-prepared spherical cobalt core before the galvanic replacement reaction, this bimetallic nanostructure exhibited enhanced coercivity as a result of surface anisotropy. A possible mechanism for the formation of this flake-like nanostructure is proposed.